AGREEMENT AND PLAN OF MERGER

EXHIBIT 2.1

EXECUTION COPY

AGREEMENT AND PLAN OF MERGER

by and among

THIRD WAVE TECHNOLOGIES, INC.

HOLOGIC, INC.

and

THUNDER TECH CORP.

Dated as of June 8, 2008

Table of Contents

ARTICLE I DEFINITIONS					2
Section 1.1		Definitions			2
Section 1.2		Terms Generally			11
ARTICLE II					11
THE OFFER					11
Section 2.1		The Offer			11
Section 2.2		Company Actions			15
Section 2.3		Company Board of Directors and Committees			17
Section 2.4		Top-Up Option			19
ARTICLE III MERGER					20
Section 3.1		The Merger			20
Section 3.2		Closing			21
Section 3.3		Effective Time			21
Section 3.4		Effects of the Merger			21
Section 3.5		Organizational Documents			21
Section 3.6		Directors and Officers of Surviving Corporation			21
ARTICLE IV EFFECT OF THE MERGER ON CAPITAL STOCK					22
Section 4.1		Conversion of Securities			22
Section 4.2		Payment of Cash for Merger Shares			22
Section 4.3		Treatment of Options, Restricted Stock Units and Other Awards			24
Section 4.4		Dissenting Shares			26
Section 4.5		Further Assurances			27
ARTICLE V REPRESENTATIONS AND WARRANTIES OF THE COMPANY					27
Section 5.1		Corporate Existence and Power			27
Section 5.2		Corporate Authorization			28
Section 5.3		Governmental Authorization			28
Section 5.4		Non-Contravention			29
Section 5.5		Capitalization			29
Section 5.6		Company Subsidiaries			31
Section 5.7		Reports and Financial Statements			31
Section 5.8		Absence of Certain Changes or Events			33
Section 5.9		Litigation			33
Section 5.10		Contracts			34
Section 5.11		Intellectual Property			34
Section 5.12		Environmental Matters			36
Section 5.13		Taxes			36
Section 5.14		Employee Benefit Plans			39
Section 5.15		Property			41

Section 5.16		Compliance With Laws			42
Section 5.17		Finders’ Fees and Fee Amounts			42
Section 5.18		Opinion of Financial Advisors			43
Section 5.19		Affiliate Transactions			43
Section 5.20		Anti-Takeover Provisions			43
Section 5.21		No Undisclosed Material Liabilities			43
Section 5.22		Suppliers			44
Section 5.23		Insurance			44
Section 5.24		Certain Business Practices			44
Section 5.25		Regulatory Compliance			44
ARTICLE VI REPRESENTATIONS AND WARRANTIES OF PARENT AND MERGER SUB					47
Section 6.1		Corporate Existence and Power			47
Section 6.2		Corporate Authorization			47
Section 6.3		Governmental Authorization			48
Section 6.4		Non-Contravention			48
Section 6.5		Financing			48
Section 6.6		Operations of Merger Sub			49
Section 6.7		Litigation			49
Section 6.8		Ownership of Shares			49
Section 6.9		No Vote of Parent Stockholders			49
Section 6.10		Management Agreements			50
Section 6.11		Acknowledgement of Disclaimer of Other Representations and Warranties			50
ARTICLE VII CONDUCT OF BUSINESS PENDING THE MERGER					50
Section 7.1		Conduct of the Company and Subsidiaries.:			50
Section 7.2		Conduct of Parent and Merger Sub			54
Section 7.3		No Control of Other Party’s Business			55
Section 7.4		Operations of Merger Sub			55
Section 7.5		Ownership of Shares			55
Section 7.6		Stock Purchase Plan Termination			55
ARTICLE VIII ADDITIONAL AGREEMENTS					55
Section 8.1		Board of Directors Recommendation Actions			55
Section 8.2		Stockholder Meeting; Short Form Merger			55
Section 8.3		Proxy Material			56
Section 8.4		Commercially Reasonable Efforts			57
Section 8.5		Access to Information			59
Section 8.6		Non-Solicitation and Recommendation Withdrawal			60
Section 8.7		Director and Officer Liability			63
Section 8.8		Takeover Statutes			65
Section 8.9		Public Announcements			65
Section 8.10		Notice of Current Events			65
Section 8.11		Employee Matters			66
Section 8.12		Stock Exchange Listing			67

Section 8.13		Section 16(b)			67
Section 8.14		Stockholder Litigation			67
Section 8.15		Conveyance Taxes			67
Section 8.16		Obligations of Merger Sub and Surviving Corporation			67
Section 8.17		Parent Representatives			68
Section 8.18		Company Warrants			68
Section 8.19		Convertible Notes			68
Section 8.20		TWT Japan Securities			69
Section 8.21		[RESERVED]			69
Section 8.22		Cooperation with Respect to Financing			69
ARTICLE IX CONDITIONS TO THE MERGER					70
ARTICLE X TERMINATION					70
Section 10.1		Termination Prior to Acceptance Time			70
Section 10.2		Termination After Acceptance Time and Prior to Effective Time			72
Section 10.3		Termination Fee			72
Section 10.4		Notice of Termination; Effect of Termination			74
ARTICLE XI MISCELLANEOUS					74
Section 11.1		Notices			74
Section 11.2		Representations and Warranties			75
Section 11.3		Expenses			76
Section 11.4		Amendment			76
Section 11.5		Waiver			76
Section 11.6		Successors and Assigns			76
Section 11.7		Governing Law			76
Section 11.8		Counterparts; Effectiveness; Third Party Beneficiaries			76
Section 11.9		Severability			77
Section 11.10		Entire Agreement			77
Section 11.11		Specific Performance			77
Section 11.12		Jurisdiction			77
Section 11.13		Authorship			78
Annex A		Conditions to Offer

AGREEMENT AND PLAN OF MERGER

     This AGREEMENT AND PLAN OF MERGER (this “ Agreement ”) is made and entered into as of this 8th day of June, 2008, by and among Third Wave Technologies, Inc., a Delaware corporation (the “ Company ”), Hologic, Inc., a Delaware corporation (“ Parent ”), and Thunder Tech Corp., a Delaware corporation, and wholly owned subsidiary of Parent (“ Merger Sub ”).

RECITALS

     WHEREAS, the respective boards of directors of Parent, Merger Sub and the Company each have determined that it is in the best interests of their respective stockholders for Parent to acquire the Company on the terms and subject to the conditions set forth in this Agreement;

     WHEREAS, in furtherance of the acquisition of the Company by Parent, Merger Sub shall commence a tender offer (the “ Offer ”) to acquire all of the outstanding shares of common stock, par value $0.001 per share, of the Company (the “ Shares ” or the “ Common Stock ”), at a price of Eleven Dollars and Twenty Five Cents ($11.25) per Share, net to the holder thereof in cash (such amount, or any different amount per Share that may be paid pursuant to the Offer in accordance with the terms hereof, being hereinafter referred to as the “ Offer Price ”), on the terms and subject to the conditions set forth herein;

     WHEREAS, following the consummation of the Offer, Merger Sub will merge with and into the Company, with the Company as the surviving corporation in the merger (the “ Merger ”), and each Share that is not tendered and accepted pursuant to the Offer will thereupon be cancelled and converted into the right to receive cash in an amount equal to the Offer Price, on the terms and subject to the conditions set forth herein;

     WHEREAS, in accordance with the General Corporation Law of the State of Delaware (the “ DGCL ”), the Board of Directors of the Company has (i) determined that this Agreement and the transactions contemplated hereby, including the Offer and the Merger, are advisable, fair to and in the best interests of the Company’s stockholders, (ii) approved the execution, delivery and performance of this Agreement and the consummation of the transactions contemplated hereby, including the Offer and the Merger, on the terms and subject to the conditions set forth herein, and adopted this Agreement, and (iii) subject to the provisions of Section 8.6(d) , resolved to recommend the acceptance of the Offer as well as the adoption of this Agreement and the approval of the transactions contemplated hereby to the stockholders of the Company;

     WHEREAS, the respective boards of directors of Parent and Merger Sub have unanimously approved this Agreement and the transactions contemplated hereby, including the Offer and the Merger, and have declared it advisable for Parent and Merger Sub, respectively, to enter into this Agreement; and

     WHEREAS, the Company, Parent and Merger Sub desire to make certain representations, warranties, covenants and agreements in connection with the Offer and the Merger and also to prescribe certain conditions to the Offer and the Merger, as set forth herein.

AGREEMENT

     NOW, THEREFORE, in consideration of the foregoing and the representations, warranties, covenants and agreements contained herein, as well as other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, intending to be legally bound, the parties hereto agree as follows:

ARTICLE I
DEFINITIONS

     Section 1.1 Definitions . For purposes of this Agreement, the following terms have the respective meanings set forth below:

     “ 2000 Stock Plan ” means the Company’s 2000 Stock Plan.

     “ Acceptable Confidentiality Agreement ” has the meaning set forth in Section 8.6(h)(i) .

     “ Acceptance Date ” has the meaning set forth in Section 2.1(e) .

     “ Acceptance Time ” has the meaning set forth in Section 2.1(e) .

     “ Actual Warrant Consideration ” means the Major Transaction Warrant Redemption Price (as defined in the Company Warrants).

     “ Adjusted Outstanding Share Number ” means the sum of (i) the aggregate number of Shares of Common Stock outstanding immediately prior to the Acceptance Time, plus (ii) at the election of Parent, an additional number of shares up to but not exceeding the aggregate number of shares of Common Stock issuable upon the exercise of (x) any outstanding Company Option (or portion thereof) that is vested or is expected to become vested by its terms (other than by reason of the Merger) on or before the Expiration Date, (y) any Company Warrant, or (z) any other right to acquire Common Stock upon exercise or conversion thereof on or before the Expiration Date, including, without limitation, any shares issuable upon exercise of Company Restricted Stock Units or conversion of the Convertible Notes.

     “ Affected Employee ” has the meaning set forth in Section 8.11(a) .

     “ Affiliate ” means, with respect to any Person, any other Person, directly or indirectly, controlling, controlled by, or under common control with, such Person. For purposes of this definition, the term “ control ” (including the correlative terms “ controlling ”, “ controlled by ” and “ under common control with ”) means the possession, directly or indirectly, of the power to direct or cause the direction of the management and policies of a Person, whether through the ownership of voting securities, by contract or otherwise.

     “ Agreement ” has the meaning set forth in the Preamble.

     “ Award Exchange Ratio ” has the meaning set forth in Section 4.3(a) .

     “ Bankruptcy and Equity Exception ” has the meaning set forth in Section 5.2(b) .

     “ Board of Directors ” means the board of directors of the Company.

     “ Business Day ” means any day other than the days on which banks in New York, New York are required or authorized to close.

     “ Certificate ” has the meaning set forth in Section 4.1(c) .

     “ Certificate of Merger ” has the meaning set forth in Section 3.3 .

     “ Closing ” has the meaning set forth in Section 3.2 .

     “ Closing Date ” has the meaning set forth in Section 3.2 .

     “ Code ” means the Internal Revenue Code of 1986, as amended.

     “ Common Stock ” has the meaning set forth in the Recitals.

     “ Company ” has the meaning set forth in the Preamble.

     “ Company Acquisition Proposal ” has the meaning set forth in Section 8.6(h)(ii) .

     “ Company Balance Sheet ” has the meaning set forth in Section 5.21(a)(i) .

     “ Company Benefit Plans ” means each Employee Benefit Plan (other than any Company Incentive Plan) and each other material employee benefit agreement, plan, program, policy or arrangement that is maintained, sponsored or contributed to by the Company or any of its Subsidiaries or ERISA Affiliates, or under which the Company, any of its Subsidiaries or any ERISA Affiliates has or may have any material liability.

     “ Company Disclosure Letter ” has the meaning set forth in the preamble to Article V .

     “ Company Employees ” means any current, former or retired employee, officer, consultant, independent contractor or director of the Company or any of its Subsidiaries.

     “ Company Financial Statements ” has the meaning set forth in Section 5.7(b) .

     “ Company Incentive Plans ” means the plans listed on Section 5.14(b) of the Company Disclosure Letter whereby Company Options, shares of Common Stock or Company Restricted Stock Units have been or may be issued to Company Employees.

     “ Company Intellectual Property Rights ” has the meaning set forth in Section 5.11(b) .

     “ Company Options ” means outstanding options to acquire Shares from the Company granted under the Company Incentive Plans.

     “ Company Proxy Statement ” has the meaning set forth in Section 8.3(a) .

     “ Company Restricted Stock Units ” means restricted stock units granted under the Company’s 2000 Stock Plan.

     “ Company Rights ” has the meaning set forth in Section 5.5(a) .

     “ Company Rights Plan ” has the meaning set forth in Section 5.5(a) .

     “ Company SEC Reports ” has the meaning set forth in Section 5.7(a) .

     “ Company Securities ” has the meaning set forth in Section 5.5(c) .

     “ Company Stockholder Meeting ” has the meaning set forth in Section 8.2(a) .

     “ Company Stockholders ” has the meaning set forth in Section 2.1(g) .

     “ Company Termination Fee ” has the meaning set forth in Section 10.3(d) .

     “ Company Warrants ” means outstanding warrants to purchase Shares from the Company.

     “ Compensation Committee ” means the compensation committee of the Board of Directors.

     “ Confidentiality Agreement ” means the letter agreement, dated as of March 25, 2008, by and between the Company and Parent.

     “ Continuing Director ” has the meaning set forth in Section 2.3(a).

     “ Contract ” has the meaning set forth in Section 5.4 .

     “ Convertible Notes ” means the Company’s 6.00% Convertible Senior Subordinated Zero-Coupon Promissory Notes due December 18, 2011.

     “ Current Policy ” has the meaning set forth in Section 8.7(b) .

     “ Damages ” has the meaning set forth in Section 8.7(a) .

     “ Debt Commitment ” has the meaning set forth in Section 6.5(a) .

     “ Debt Commitment Letter ” has the meaning set forth in Section 6.5(a) .

     “ Debt Financing ” has the meaning set forth in Section 6.5(a) .

     “ Delaware Law ” shall mean the DGCL and any other applicable law of the State of Delaware.

     “ DGCL ” has the meaning set forth in the Recitals.

     “ Director Percentage ” has the meaning set forth in Section 2.3(a) .

     “ Dissenting Shares ” has the meaning set forth in Section 4.4 .

     “ DOJ ” has the meaning set forth in Section 8.4(c) .

     “ Effective Time ” has the meaning set forth in Section 3.3 .

     “ Employee Benefit Plan ” has the meaning set forth in Section 3(3) of ERISA.

     “ Environmental Laws ” means any federal, state, local or foreign law, statute, ordinance, rule, regulation, code, license, permit, authorization, approval, consent, order, judgment, decree, injunction, requirement or agreement with any governmental entity relating to (x) the protection, preservation or restoration of the environment, or (y) the exposure to, or the use, storage, recycling, treatment, generation, transportation, processing, handling, labeling, production, release or disposal of Hazardous Substances, in each case as in effect at the date hereof.

     “ ERISA ” means the Employee Retirement Income Security Act of 1974, as amended.

     “ ERISA Affiliate ” means any entity that, together with the Company would be treated as a single employer under Section 414 of the Code.

     “ Estimated Warrant Consideration ” means the Major Transaction Warrant Redemption Price (as defined in the Company Warrants) to be estimated three Business Days prior to the Closing Date as provided in Section 5(c)(iv) of the Company Warrants.

     “ Exchange Act ” means the Securities Exchange Act of 1934, as amended, and the rules and regulations promulgated thereunder.

     “ Expiration Date ” has the meaning set forth in Section 2.1(d) .

     “ FDA ” means the United States Food and Drug Administration.

     “ FDCA ” has the meaning set forth in Section 5.16(b) .

     “ Financing Agreements ” has the meaning set forth in Section 8.22(a).

     “ FTC ” has the meaning set forth in Section 8.4(c) .

     “ GAAP ” means United States generally accepted accounting principles as of the date hereof, consistently applied.

     “ Governmental Authority ” means any nation or government or any agency, public or regulatory authority, instrumentality, department, commission, court, arbitrator, ministry, tribunal or board of any nation or government or political subdivision thereof, in each case, whether national, federal, provincial, state, regional, local or municipal.

     “ GSCP” has the meaning set forth in Section 6.5(a).

     “ Hazardous Substances ” means any substance presently listed, defined, designated or classified as hazardous, toxic, radioactive, or dangerous under any Environmental Law.

     “ HSR Act ” means the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended.

     “ Independent Directors ” has the meaning set forth in Section 2.3(b) .

     “ Initial Expiration Date ” has the meaning set forth in Section 2.1(d) .

     “ Insurance Amount ” has the meaning set forth in Section 8.7(b) .

     “ Intellectual Property Rights ” means all (a) patents and patent applications, together with reissues, continuations, continuations-in-part, revisions, divisionals, extensions and reexaminations thereof, (b) trademarks, service marks, trade dress, logos, trade names and Internet domain names, and applications, registrations, and renewals in connection therewith and all goodwill associated therewith, (c) copyrights in copyrightable works, copyright registrations and applications for registration thereof and renewals thereof) and (d) trade secrets, know-how, improvements, processes, formulae and inventions.

     “ Internal Controls ” has the meaning set forth in Section 5.7(d).

     “ Intercompany Debt ” means any loan, advance or other obligation solely among the Company and/or any of its Subsidiaries.

     “ Intervening Event ” has the meaning set forth in Section 8.6(d).

     “ Investor Rights Agreement ” means the Investor Rights Agreement, dated May 31, 2007, by and among, the Company, TWT Japan and the Minority Investors.

     “ IRS ” means the Internal Revenue Service of the United States.

     “ Knowledge ” means the actual knowledge of the Persons set forth in Section 1.1 of the Company Disclosure Letter.

     “ Law ” means applicable statutes, common laws, rules, ordinances, regulations, codes, orders, judgments, injunctions, writs, decrees, governmental guidelines or interpretations having the force of law or bylaws, in each case, of a Governmental Authority. For the avoidance of doubt, the term “Law” shall include Environmental Laws.

     “ Leased Real Property ” has the meaning set forth in Section 5.15(a) .

     “ Liens ” means, with respect to any asset, any mortgage, lien, pledge, charge, security interest or encumbrance of any kind in respect of such asset.

     “ LTIP Incentive Award ” means an incentive award granted to an LTIP Participant under an LTIP.

     “ LTIP Participants ” means the executive management team and key employees who are recipients of incentive awards under an LTIP.

     “ LTIP ” means the Long Term Incentive Plan No. 2, Amended Long Term Incentive Plan No. 3, Long Term Incentive Plan No. 4 or the Long Term Incentive Plan No. 5 of the Company.

     “ Material Adverse Effect on the Company ” means any event, state of facts, circumstance, development, change, effect or occurrence that is or would reasonably be expected to be materially adverse to the business, financial condition or results of operations of the Company and its Subsidiaries, taken as a whole, other than any event, state of facts, circumstance, development, change, effect or occurrence resulting from (A) changes in general economic or political conditions or the securities, credit or financial markets in general, (B) general changes or developments in the business in which the Company and its Subsidiaries operate, including any changes in applicable Law affecting such business, including generally applicable rules, regulations and administrative policies of the FDA, or published interpretations thereof, (C) the announcement of this Agreement or the pendency of the transactions contemplated hereby, including any fees or expenses incurred in connection therewith, (D) the identity of Parent or any of its Affiliates as the acquiror of the Company, (E) compliance with the terms of, or the taking of any action required to be taken by this Agreement or consented to by Parent, (F) any acts of terrorism or war or any natural disaster or weather-related event, (G) changes in generally accepted accounting principles or the interpretation thereof, (H) changes in the price or trading volume of the Common Stock (provided that this clause (H) shall not be construed as providing that the change, event, circumstance, development, occurrence or state of facts giving rise to such change in price or trading volume does not constitute or contribute to a Material Adverse Effect on the Company), (I) any failure to meet internal or published projections, forecasts or revenue or earning predictions or any downward revisions for any period (provided that this clause (I) shall not be construed as providing that the change, event, circumstance, development, occurrence or state of facts giving rise to such failure does not constitute or contribute to a Material Adverse Effect on the Company), or (J) any legal proceedings made or brought by any of the current, former or future stockholders of the Company (on their own behalf or on behalf of the Company) arising out of or related to this Agreement or the Merger, except, in the case of the foregoing clause (A), (B) or (F), to the extent such changes or developments referred to therein would reasonably be expected to have a materially disproportionate negative impact on the Company and its Subsidiaries, taken as a whole, compared to other comparable participants in Company’s industry.

     “ Material Adverse Effect on Parent ” means any event, state of facts, circumstance, development, change, effect or occurrence that is materially adverse to the ability of Parent or Merger Sub to timely perform its obligations under this Agreement.

     “ Material Contract ” has the meaning set forth in Section 5.10(a) .

     “ Medical Product ” has the meaning set forth in Section 5.25.

     “ Merger ” has the meaning set forth in the Recitals.

     “ Merger Consideration ” has the meaning set forth in Section 4.1(c) .

     “ Merger Shares ” has the meaning set forth in Section 4.1(c) .

     “ Merger Sub ” has the meaning set forth in the Preamble.

     “ Minimum Condition ” has the meaning set forth in Section 2.1(b) .

     “ Minority Investors ” means Mitsubishi Corporation, CSK Institute for Sustainability, LTD., BML, Inc., Daiichi Pure Chemicals Co., Ltd., Toppan Printing Co., Ltd. and Shimadzu Corporation.

     “ No Fault Financing Failure ” has the meaning set forth in Section 10.1(c)(iv).

     “ Offer ” has the meaning set forth in the Recitals.

     “ Offer Documents ” has the meaning set forth in Section 2.1(g) .

     “ Offer Price ” has the meaning set forth in the Recitals.

     “ Offer to Purchase ” has the meaning set forth in Section 2.1(g) .

     “ Outside Date ” has the meaning set forth in Section 2.1(d) .

     “ Parent ” has the meaning set forth in the Preamble.

     “ Parent Closing Value ” means the average closing price of a share of Parent Common Stock for the five trading days ending on the trading day immediately prior to the Effective Time.

     “ Parent Common Stock ” means the common stock, par value $0.01 per share, of Parent.

     “ Parent Disclosure Letter ” has the meaning set forth in the preamble to Article VI .

     “ Parent Representative ” has the meaning set forth in Section 8.17.

     “ Paying Agent ” has the meaning set forth in Section 4.2(a) .

     “ Permits ” means any licenses, franchises, permits, certificates, consents, approvals or other similar authorizations of, from or by a Governmental Authority, possessed by, granted to or necessary for the ownership of the material assets or conduct of the business of the Company or its Subsidiaries.

     “ Permitted Liens ” means (i) Liens for Taxes, assessments and governmental charges or levies not yet due and payable or that are being contested in good faith and by appropriate Proceedings; (ii) mechanics, carriers’, workmen’s, repairmen’s, materialmen’s or other Liens or security interests that are incurred in the ordinary course of business for amounts which are not delinquent and, in each case that do not adversely affect in any material respect the current use of the applicable property owned, leased, used or held for use by the Company or any of its Subsidiaries or are being contested in good faith and by appropriate Proceedings; (iii) leases, subleases and non-exclusive licenses in the ordinary course of business; (iv) Liens imposed by applicable Laws (other than any such Lien imposed pursuant to Section 430(k) of the Internal Revenue Code or by Section 303(k) of ERISA), (v) pledges or deposits to secure obligations under workers’ compensation Laws or similar legislation or to secure public or statutory obligations; (vi) pledges and deposits to secure the performance of bids, trade contracts, leases, surety and appeal bonds, performance bonds and other obligations of a similar nature, in each

case in the ordinary course of business; (vii) easements, covenants, conditions, restrictions and rights of way and other similar restrictions (in any case either unrecorded and of record), and zoning, building, title defects and other similar restrictions related to the use of real property, in each case that do not adversely affect in any material respect the current use of the real property; and (viii) non-exclusive licenses relating to Intellectual Property Rights granted in the ordinary course of business prior to the date of this Agreement.

     “ Person ” means any individual, corporation, company, limited liability company, partnership, association, trust, joint venture or any other entity or organization, including any government or political subdivision or any agency or instrumentality thereof.

     “ Preferred Stock ” has the meaning set forth in Section 5.5(a) .

     “ Proceeding ” has the meaning set forth in Section 5.9 .

     “ Real Property Leases ” has the meaning set forth in Section 5.15(a) .

     “ Recommendation ” has the meaning set forth in Section 2.2(a) .

     “ Recommendation Withdrawal ” has the meaning set forth in Section 8.1(a) .

     “ Regulatory Law ” has the meaning set forth in Section 8.4(e).

     “ Regulatory Law Condition ” has the meaning set forth on Annex A .

     “ Representatives ” has the meaning set forth in Section 8.6(a) .

     “ Requisite Stockholder Vote ” has the meaning set forth in Section 5.2(a) .

     “ Revised Exercise Date ” means the purchase date specified in the notice sent to participants in the Stock Purchase Plan, which date shall be prior to the Effective Time.

     “ Rights Plan Amendment ” has the meaning set forth in Section 2.2(a) .

     “ Sarbanes-Oxley Act ” means the Sarbanes-Oxley Act of 2002, as amended, including the rules and regulations promulgated thereunder.

     “ Schedule 14D-9 ” has the meaning set forth in Section 2.2(b) .

     “ Schedule TO ” has the meaning set forth in Section 2.1(g) .

     “ SEC ” means the United States Securities and Exchange Commission.

     “ Securities Act ” means the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder.

     “ Shares ” has the meaning set forth in the Recitals.

     “ Social Security Act ” has the meaning set forth in Section 5.25(f)

     “ Stock Purchase Plan ” has the meaning set forth in Section 4.3(d) .

     “ Subsidiary ”, with respect to any Person, means any other Person of which the first Person owns, directly or indirectly, securities or other ownership interests having either (i) voting power to elect a majority of the board of directors or other persons performing similar functions, or (ii) beneficial ownership of more than 50% of the equity interests of the second Person.

     “ Superior Proposal ” has the meaning set forth in Section 8.6(h)(iii) .

     “ Surviving Corporation ” has the meaning set forth in Section 3.1 .

     “ Surviving Corporation Plan ” has the meaning set forth in Section 8.11(b) .

     “ Takeover Statute ” has the meaning set forth in Section 5.20(a) .

     “ Tax ” has the meaning set forth in Section 5.13(l) .

     “ Taxing Authority ” has the meaning set forth in Section 5.13(l) .

     “ Tax Return ” has the meaning set forth in Section 5.13(l) .

     “ Tax Sharing Agreement ” has the meaning set forth in Section 5.13(l) .

     “ Termination Fee ” means $18,000,000 in cash.

     “ Tender Offer Conditions ” has the meaning set forth in Section 2.1(b ).

     “ Third Party ” has the meaning set forth in Section 8.6(a) .

     “ Top-Up Option ” has the meaning set forth in Section 2.4(a) .

     “ Top-Up Option Shares ” has the meaning set forth in Section 2.4(a).

     “ TWT Japan ” means Third Wave Japan, Inc., an entity organized under the laws of Japan and a Subsidiary of the Company.

     “ TWT Japan Securities ” means all common stock and preferred stock issued by TWT Japan.

     “ TWT Japan Warrants ” means outstanding warrants to purchase shares of TWT Japan common stock.

     “ United States Jurisdiction ” means the United States of America, its territories and possessions.

     “ Warrant Escrow Account ” has the meaning set forth in Section 8.18 .

      Section 1.2 Terms Generally . The definitions in Section 1.1 shall apply equally to both the singular and plural forms of the terms defined. Whenever the context may require, any pronoun shall include the corresponding masculine, feminine and neuter forms. The words “include”, “includes” and “including” shall be deemed to be followed by the phrase “without limitation”, unless the context expressly provides otherwise. All references herein to Sections, paragraphs, subparagraphs, clauses, Exhibits or Schedules shall be deemed references to Sections, paragraphs, subparagraphs or clauses of, or Exhibits or Schedules to this Agreement, unless the context requires otherwise. Unless otherwise expressly defined, terms defined in this Agreement have the same meanings when used in any Exhibit or Schedule hereto, including the Company Disclosure Letter. Unless otherwise specified, the words “this Agreement”, “herein”, “hereof”, “hereto” and “hereunder” and other words of similar import refer to this Agreement as a whole (including the Schedules, Exhibits and the Company Disclosure Letter) and not to any particular provision of this Agreement. The term “or” is not exclusive. The word “extent” in the phrase “to the extent” shall mean the degree to which a subject or other thing extends, and such phrase shall not mean simply “if”. Any Contract, instrument or Law defined or referred to herein means such Contract, instrument or Law as from time to time amended, modified or supplemented, including (in the case of Contracts or instruments) by waiver or consent and (in the case of Laws) by succession of comparable successor Laws and references to all attachments thereto and instruments incorporated therein. References to a Person are also to such Person’s permitted successors and assigns.

ARTICLE II

     Section 2.1 The Offer .

          (a) Commencement of the Offer . Provided that this Agreement shall not have been terminated pursuant to Section 10.1 hereof, as promptly as practicable after the date hereof (but in no event more than ten (10) Business Days thereafter), Parent shall cause Merger Sub to, and Merger Sub shall commence (within the meaning of Rule 14d-2 promulgated under the Exchange Act) the Offer to Purchase all of the Shares at a price per Share equal to the Offer Price (as adjusted as provided in Section 2.1(c) , if applicable) and in compliance with Rule 14d-11 promulgated under the Exchange Act and all other provisions of applicable securities laws.

          (b) Terms and Conditions of the Offer . The obligation of Merger Sub to accept for payment and to pay for any Shares tendered (and the obligation of Parent to cause Merger Sub to accept for payment and to pay for any Shares tendered) in the Offer shall be subject only to: (i) the condition that, prior to the then scheduled expiration date of the Offer (as it may be extended from time to time pursuant to Section 2.1(d) ), there be validly tendered in accordance with the terms of the Offer and not withdrawn a number of Shares that, together with the Shares then owned by Parent and Merger Sub (if any), and without giving effect to any treasury shares of Common Stock, represents more than fifty percent (50%) of the Adjusted Outstanding Share Number (the “ Minimum Condition ”); and (ii) the other conditions set forth in Annex A hereto (together with the Minimum Condition, the “ Tender Offer Conditions ”). The

conditions to the Offer set forth in Annex A hereto are for the sole benefit of Parent and Merger Sub and may be waived by Parent and Merger Sub, in whole or in part, at any time and from time to time, in their sole discretion, other than the Minimum Condition, which may be waived by Parent and Merger Sub only with the prior written consent of the Company. Parent and Merger Sub expressly reserve the right to increase the Offer Price or to make any other changes in the terms and conditions of the Offer; provided , however , that unless otherwise provided in this Agreement or previously approved by the Company in writing, neither Parent nor Merger Sub may make any change to the terms or conditions of the Offer that (A) decreases the Offer Price, (B) changes the form of consideration to be paid in the Offer, (C) reduces the number of Shares sought to be purchased in the Offer, (D) imposes conditions to the Offer in addition to the conditions to the Offer set forth in Annex A hereto, (E) amends the conditions to the Offer set forth in Annex A hereto so as to broaden the scope of such conditions to the Offer, (F) extends the Offer in any manner other than pursuant to and in accordance with the terms of Section 2.1(d) , (G) amends or waives the Minimum Condition, or (H) otherwise amends any other term or condition of the Offer in a manner adverse to the holders of Shares.

          (c) Adjustments to Offer Price . The Offer Price shall be adjusted appropriately to reflect the effect of any stock split, reverse stock split, stock dividend (including any dividend or distribution of securities convertible into Common Stock), cash dividend, reorganization, recapitalization, reclassification, combination, exchange of shares or other like change with respect to Common Stock occurring on or after the date hereof and prior to Merger Sub’s acceptance for payment of, and payment for, Shares pursuant to the Offer.

          (d) Expiration and Extension of the Offer . Subject to the terms and conditions of this Agreement and the Offer, the Offer shall initially be scheduled to expire at midnight, New York Time, on the date that is twenty (20) business days (for this purpose calculated in accordance with Rule 14d-1(g)(3) promulgated under the Exchange Act) after the date the Offer is commenced (within the meaning of Rule 14d-2 promulgated under the Exchange Act)(the “ Initial Expiration Date ”). Notwithstanding the foregoing or anything to the contrary set forth in this Agreement, (i) Merger Sub shall extend the Offer for any period required by any rule, regulation, interpretation or position of the SEC or the staff of the SEC or the Nasdaq Global Select Market that is applicable to the Offer, (ii) in the event that any of the conditions to the Offer set forth on Annex A hereto are not satisfied or waived as of any then scheduled expiration date of the Offer, Merger Sub shall extend the Offer for successive extension periods of not more than ten (10) Business Days each in order to permit the satisfaction of the conditions to the Offer (the Initial Expiration Date, or such later date to which the Initial Expiration Date has been extended pursuant to and in accordance with the terms of this Agreement, is referred to as the “ Expiration Date ”); provided , however , that notwithstanding the foregoing clauses (i) and (ii) of this Section 2.1(d) , in no event shall Merger Sub be required to extend the Offer beyond the earlier to occur of (A) the date this Agreement is terminated pursuant to Section 10.1 hereof or (B) the date that is 180 days after the date hereof (the “ Outside Date ”); and provided further , that the foregoing clauses (i) and (ii) of this Section

2.1(d) shall not be deemed to impair, limit or otherwise restrict in any manner the right of Parent to terminate this Agreement pursuant to Section 10.1 hereof, and (iii) Merger Sub may, in its discretion (and without the consent of the Company or any other Person), elect to provide for a subsequent offering period (and one or more extensions thereof) in accordance with Section 2.1(f) . Merger Sub shall not and Parent agrees that it shall cause Merger Sub not to terminate or withdraw the Offer other than in connection with an effective termination of this Agreement pursuant to Section 10.1 .

          (e) Payment for Shares . Unless earlier terminated in accordance with Article X hereof, upon satisfaction of the Tender Offer Conditions, Parent shall cause Merger Sub to, and Merger Sub shall, accept for payment and pay for all Shares validly tendered and not withdrawn pursuant to the Offer as promptly as practicable after the first Expiration Date on which the Tender Offer Conditions are satisfied (the date of acceptance for payment, the “ Acceptance Date ” and the time of acceptance for payment on the Acceptance Date, the “ Acceptance Time ”) and in any event in compliance with Rule 14e-1(c) promulgated under the Exchange Act. The Offer Price payable in respect of each Share validly tendered and not withdrawn pursuant to the Offer or any subsequent offering period contemplated by Section 2.1(f) shall be paid net to the holder thereof in cash, without interest and less any amounts required to be deducted and withheld under any applicable Tax law. Parent shall provide, or cause to be provided to Merger Sub, on a timely basis, the funds necessary to pay for any shares of Common Stock that Merger Sub accepts or is obligated to accept for payment pursuant to the Offer.

          (f) Subsequent Offering Period . Merger Sub may, and the Offer Documents shall reserve the right of Merger Sub to, extend the Offer for a subsequent offering period (within the meaning of Rule 14d-11 promulgated under the Exchange Act) in compliance with Rule 14d-11 promulgated under the Exchange Act and all other provisions of applicable securities laws of not less than three (3) nor more than twenty (20) business days (for this purpose calculated in accordance with Rule 14d-1(g)(3) promulgated under the Exchange Act) immediately following the Expiration Date; provided , however , that in the event that more than fifty percent (50%) but less than ninety percent (90%) of the then outstanding Shares have been validly tendered and not withdrawn pursuant to the Offer on the applicable Expiration Date, Merger Sub shall extend the Offer for a subsequent offering period (within the meaning of Rule 14d-11 promulgated under the Exchange Act) of ten (10) business days (for this purpose calculated in accordance with Rule 14d-1(g)(3) promulgated under the Exchange Act) immediately following the Expiration Date. Subject to the terms and conditions set forth in this Agreement and the Offer, Parent shall cause Merger Sub to, and Merger Sub shall, accept for payment and pay for all Shares validly tendered and not withdrawn pursuant to the Offer as so extended by such subsequent offering period as promptly as practicable after any such Shares are tendered during such subsequent offering period and in any event in compliance with Rule 14e-1(c) promulgated under the Exchange Act.

          (g) Schedule TO; Offer Documents . As soon as practicable on the date the Offer is commenced (within the meaning of Rule 14d-2 promulgated under the

Exchange Act), Parent and Merger Sub shall: (i) file with the SEC a Tender Offer Statement on Schedule TO (together with all amendments and supplements thereto, and including all exhibits thereto, the “ Schedule TO ”) with respect to the Offer, which shall contain as an exhibit or incorporate by reference an offer to purchase (the “ Offer to Purchase ”), and forms of the related letter of transmittal, a summary advertisement, if any, in respect of the Offer, and such other ancillary documents and instruments pursuant to which the Offer will be made or which are required to be filed in connection with the filing of the Schedule TO (collectively, together with any supplements or amendments thereto, the “ Offer Documents ”); and (ii) cause the Offer Documents to be disseminated to all holders of Shares (collectively, the “ Company Stockholders ”). The Company shall promptly after the date hereof furnish to Parent and Merger Sub in writing all information concerning the Company that may be required by applicable securities laws or reasonably requested by Parent or Merger Sub for inclusion in the Schedule TO and the Offer Documents. Parent and Merger Sub shall cause the Schedule TO and the Offer Documents to comply in all material respects with the Exchange Act and all other applicable Laws. Parent and Merger Sub hereby further agree that the Schedule TO and the Offer Documents, when filed with the SEC and on the date first published, sent or given to the Company Stockholders, shall not contain any untrue statement of a material fact or omit to state any material fact required to be stated therein or necessary in order to make the statements therein, in light of the circumstances under which they were made, not misleading; provided , however , that no representation or warranty is made by Parent or Merger Sub with respect to information supplied by the Company in writing specifically for inclusion or incorporation by reference in the Schedule TO or the Offer Documents. The Company hereby agrees that the information provided by the Company in writing specifically for inclusion or incorporation by reference in the Schedule TO or the Offer Documents shall not contain any untrue statement of a material fact or omit to state any material fact required to be stated therein or necessary in order to make the statements therein, in light of the circumstances under which they were made, not misleading. Each of Parent, Merger Sub and the Company shall promptly correct any information provided by it for use in the Schedule TO or the Offer Documents if and to the extent that such information shall have become false or misleading in any material respect. Parent and Merger Sub shall take all steps necessary to cause the Schedule TO and the Offer Documents, as so corrected, to be filed with the SEC and the other Offer Documents, as so corrected, to be disseminated to the Company Stockholders, in each case as and to the extent required by applicable federal securities laws. Parent and Merger Sub shall provide the Company and its counsel a reasonable opportunity to review and comment on the Schedule TO and the Offer Documents prior to the filing thereof with the SEC. Parent and Merger Sub shall provide to the Company and its counsel any and all written comments that Parent, Merger Sub or their counsel may receive in writing from the SEC or its staff with respect to the Schedule TO and the Offer Documents promptly after receipt thereof, and Parent and Merger Sub shall provide the Company and its counsel a reasonable opportunity to participate in the formulation of any written response to any such written comments of the SEC or its staff.

              (h) Legal Requirements . Without limiting the foregoing, Parent and Merger Sub shall take all reasonable actions to cause the Offer to be conducted in accordance with all applicable Laws.

   Section 2.2 Company Actions .

              (a) Company Determinations, Approvals and Recommendations . At a meeting duly called and held prior to the date hereof, the Board of Directors has unanimously:

               (i) determined that this Agreement and the transactions contemplated hereby, including the Offer and the Merger, are advisable, fair to and in the best interests of the Company’s stockholders;

               (ii) approved this Agreement and the transactions contemplated hereby, including the Offer and the Merger, on the terms and subject to the conditions set forth herein;

               (iii) to the extent necessary, adopted a resolution for the purpose of causing Parent and Merger Sub not to be subject to any restriction set forth in any state takeover law or similar Law that might otherwise apply to the Offer, the Merger or any of the other transactions contemplated hereby;

               (iv) authorized the taking of all actions necessary to amend the Company Rights Plan to confirm that (i) neither the execution, delivery or performance of this Agreement nor the consummation of the transactions contemplated hereby will (A) cause the Company Rights to become exercisable, (B) cause Parent or any of its Affiliates or Associates (each as defined in the Company Rights Plan) to become an Acquiring Person (as defined in the Company Rights Plan) or (C) give rise to a Distribution Date or Shares Acquisition Date (each as defined in the Company Rights Plan) and (ii) the Company Rights will expire in their entirety immediately prior to the Effective Time without any payment being made in respect thereof (the “ Rights Plan Amendment ”);

               (v) taken such action as is required under the Stock Purchase Plan to provide that there may not be any increases in any Stock Purchase Plan participants’ payroll deduction rates during any Stock Purchase Plan offering period prior to the Effective Date; and

               (vi) resolved to recommend that the holders of Shares accept the Offer, tender their Shares to Merger Sub pursuant to the Offer and, if required by Delaware Law, adopt this Agreement in accordance with the applicable provisions of Delaware Law; provided , however , that such recommendation was made subject to the understanding that it may be withheld, withdrawn, amended or modified in accordance with the terms of Section 8.6(d) (the “ Recommendation ”).

              (b) Schedule 14D-9 . Promptly after the commencement of the Offer (within the meaning of Rule 14d-2 promulgated under the Exchange Act) and in any event with ten (10) business days (for this purpose calculated in accordance with Rule 14d-1(g)(3) promulgated under the Exchange Act) thereafter, the Company shall (i)

file with the SEC a Solicitation/Recommendation Statement on Schedule 14D-9 (together with all amendments and supplements thereto, and including all exhibits thereto, the “ Schedule 14D-9 ”), and (ii) cause the Schedule 14D-9 to be mailed to the Company Stockholders. To the extent reasonably practical, the Company shall file the Schedule 14D-9 with the SEC concurrently with the filing by Parent and Merger Sub of the Schedule TO and the Schedule 14D-9 shall be mailed by Parent to the Company Stockholders with the Offer Documents (and, if so, the expense thereof shall be borne by Parent in connection with its dissemination of the Offer Documents). Subject to the provisions of Section 8.6(d) hereof, the Schedule 14D-9 shall include a description of the determinations and approvals of the Board of Directors set forth in Section 2.2(a ), including, without limitation, the Recommendation. Each of Parent and Merger Sub shall promptly after the date hereof furnish to the Company in writing all information concerning Parent and Merger Sub that may be required by applicable securities laws or reasonably requested by the Company for inclusion in the Schedule 14D-9. The Company shall cause the Schedule 14D-9 to comply in all material respects with the Exchange Act and all other applicable Laws. The Company hereby further agrees that the Schedule 14D-9, shall not contain any untrue statement of a material fact or omit to state any material fact required to be stated therein or necessary in order to make the statements therein, in light of the circumstances under which they were made, not misleading; provided , however , that no representation or warranty is made by the Company with respect to information supplied by Parent or Merger Sub or any of their officers, directors, representatives, agents or employees in writing specifically for inclusion or incorporation by reference in the Schedule 14D-9. Parent and Merger Sub hereby agree that the information provided by them specifically in writing for inclusion or incorporation by reference in the Schedule 14D-9 shall not contain any untrue statement of a material fact or omit to state any material fact required to be stated therein or necessary in order to make the statements therein, in light of the circumstances under which they were made, not misleading. Each of the Company, Parent and Merger Sub shall promptly correct any information provided by it for use in the Schedule 14D-9 if and to the extent that such information shall have become false or misleading in any material respect. The Company shall take all steps necessary to cause the Schedule 14D-9, as so corrected, to be filed with the SEC and disseminated to the Company Stockholders, in each case as and to the extent required by applicable federal securities laws. The Company shall provide Parent, Merger Sub and their counsel reasonable opportunity to review and comment on the Schedule 14D-9 prior to the filing thereof with the SEC. The Company shall provide in writing to Parent, Merger Sub and their counsel any written comments the Company or its counsel may receive in writing from the SEC or its staff with respect to the Schedule 14D-9 promptly upon receipt thereof, and the Company shall provide Parent, Merger Sub and their counsel a reasonable opportunity to participate in the formulation of any written response to any such written comments of the SEC or its staff.

          (c) Company Information . In connection with the Offer, the Company shall, or shall cause its transfer agent to, promptly following a request by Parent, furnish Parent at Parent’s sole cost and expense with such information as Parent or its agents may reasonably request in order to disseminate and otherwise communicate the Offer to the record and beneficial holders of Shares, including a list, as of the most

recent practicable date, of the stockholders of the Company, mailing labels and any available listing or computer files containing the names and addresses of all record and beneficial holders of Shares, and lists of security positions of Shares held in stock depositories (including updated lists of stockholders, mailing labels, listings or files of securities positions). Subject to any and all applicable Laws, and except for such steps as are necessary to disseminate the Offer Documents and any other documents necessary to consummate the Merger, Parent and Merger Sub shall (and shall cause their respective agents, representatives, employees, and advisors to):

               (i) hold in confidence the information contained in any such lists of stockholders, mailing labels and listings or files of securities positions on the terms and subject to the conditions set forth in the Confidentiality Agreement;

               (ii) use such information only in connection with the Offer and the Merger; and

               (iii) if (A) this Agreement shall be terminated pursuant to Section 10.1 or Section 10.2 hereof and/or (B) Parent and Merger Sub shall withdraw the Offer, and deliver (and shall use their respective reasonable efforts to cause their agents to deliver) to the Company any and all copies and any extracts or summaries from such information then in their possession or control.

   Section 2.3 Company Board of Directors and Committees .

              (a) Composition of Board of Directors and Board Committees . Effective upon the Acceptance Time and from time to time thereafter, Parent shall be entitled to designate up to such number of directors on the Board of Directors equal to the product (rounded up to the next whole number) obtained by multiplying (x) the number of directors on the Board of Directors (giving effect to any increase in the number of directors pursuant to this Section 2.3 ) and (y) a fraction, the numerator of which is the number of Shares held by Parent and Merger Sub (giving effect to the Shares purchased pursuant to the Offer), and the denominator of which is the total number of then outstanding Shares (the “ Director Percentage ”). Promptly following a request by Parent, the Company shall use its best efforts to cause the individuals so designated by Parent to be elected or appointed to the Board of Directors and, at the request of Parent, each board of directors or similar governing body of each Subsidiary of the Company, including (at the election of Parent) either by increasing the size of the Board of Directors (or the board of directors or similar governing body of the applicable Subsidiary of the Company) and electing Parent’s designees to the newly created positions or by seeking and accepting or otherwise securing the resignations of such number of then incumbent directors as is necessary to enable the individuals so designated by Parent to be elected or appointed to the Board of Directors (and the board of directors or similar governing body of the applicable Subsidiary of the Company) and electing Parent’s designees to the vacancies created by such resignations, provided that with respect to the Board of Directors of TWT Japan, Parent shall be entitled to designate such number of directors as shall be equal to the product of the (A) the Director Percentage and (B) the total number of directors the

Company is entitled to designate to the Board of Directors of TWT Japan pursuant to the requirements of the Investor Rights Agreement, rounding up to the nearest whole number. From time to time after the Acceptance Time, the Company shall take all action necessary to cause the individuals so designated by Parent to constitute substantially the same percentage (rounding up where appropriate) as is on the Board of Directors (or the board of directors or similar governing body of each Subsidiary of the Company) on each committee of the Board of Directors (and each committee of the board of directors or similar governing body of each Subsidiary of the Company) to the fullest extent permitted by all applicable Laws and the rules of the Nasdaq Global Select Market. Solely for purposes of this Section 2.3 , any and all members of the Board of Directors immediately prior to such appointments by Parent who remain on the Board of Directors after such appointments by Parent shall be referred to as “ Continuing Directors .”

          (b) Continued Listing . In the event that Parent’s designees are elected or appointed to the Board of Directors pursuant to Section 2.3(a) , until the Effective Time, the Board of Directors shall have at least such number of directors as may be required by the rules of the Nasdaq Global Select Market or the federal securities laws who are considered independent directors within the meaning of such rules and laws (“ Independent Directors ”); provided that , in such event, if the number of Independent Directors shall be reduced below the number of directors as may be required by such rules and regulations for any reason whatsoever, the remaining Independent Director(s) shall be entitled to designate persons to fill such vacancies who shall be Independent Directors or, if no other Independent Director then remains, the other directors shall designate such number of Independent Directors as may be required by the rules of the Nasdaq Global Select Market and the federal securities laws, to fill such vacancies who shall not be stockholders or Affiliates of Parent or Merger Sub. From and after the Acceptance Time and until the Effective Time, the Company shall to the extent permitted by the rules and regulations of the Nasdaq Global Select Market, elect to be treated as a “controlled company” as defined by NASDAQ Marketplace Rule 4250(c)(5) and make all necessary filings and disclosures associated with such status.

          (c) Section 14(f) of the Exchange Act . The Company’s obligation to appoint Parent’s designees to the Board of Directors pursuant to Section 2.3(a) shall be subject to Section 14(f) of the Exchange Act and Rule 14f-1 promulgated thereunder. The Company shall use its reasonable efforts to promptly take all action required pursuant to this Section 2.3 and Section 14(f) of the Exchange Act and Rule 14f-1 promulgated thereunder in order to fulfill its obligations under this Section 2.3 , and shall include in the Schedule 14D-9 such information with respect to the Company and its directors and officers as is required under such Section 14(f) and Rule 14f-1 in order to fulfill its obligations under this Section 2.3 . Parent shall provide to the Company in writing, and be solely responsible for any information with respect to itself and its nominees, directors, officers and Affiliates, required by such Section 14(f) of the Exchange Act and Rule 14f-1 promulgated thereunder.

          (d) Required Approvals of Continuing Directors . Notwithstanding anything to the contrary set forth in this Agreement, in the event that Parent’s designees are elected or appointed to the Board of Directors prior to the Effective Time pursuant to Section 2.3(a) and there shall be any Continuing Directors, the approval of a majority of such Continuing Directors (or the sole Continuing Director if there shall be only one (1) Continuing Director) shall be required in order to (i) amend or terminate this Agreement, or agree or consent to any amendment or termination of this Agreement, in any case on behalf of the Company, (ii) extend the time for performance of, or waive, any of the obligations or other acts of Parent or Merger Sub under this Agreement, (iii) waive any of the Company’s rights under this Agreement, (iv) amend, rescind, repeal or waive the certificate of incorporation or bylaws of the Company , or (v) make any other determination with respect to any action to be taken or not to be taken by or on behalf of the Company relating to this Agreement or the transactions contemplated hereby, including the Offer and the Merger.

   Section 2.4 Top-Up Option .

               (a)  Grant and Availability of Top-Up Option . The Company hereby grants to Parent and Merger Sub an irrevocable option (the “ Top-Up Option ”) to purchase, at a price per share equal to the Offer Price, a number of Shares (the “ Top-Up Option Shares ”) that, when added to the number of Shares owned by Parent or Merger Sub or any wholly owned Subsidiary of Parent or Merger Sub at the time of exercise of the Top-Up Option, constitutes 90.0005% of the number of Shares that will be outstanding immediately after the issuance of the Top-Up Option Shares. The Top-Up Option may be exercised by Parent or Merger Sub at any time on or after the Acceptance Time and on or prior to the fifth Business Day after the later of (1) the expiration date of the Offer or (2) the expiration of any subsequent offering period; provided , however , that the obligation of the Company to deliver Top-Up Option Shares upon the exercise of the Top-Up Option is subject to the conditions, unless waived by the Company, that (A) no provision of any applicable Laws and no applicable order, injunction or other judgment shall prohibit the exercise of the Top-Up Option or the delivery of the Top-Up Option Shares in respect of such exercise, (B) the issuance of Top-Up Option Shares pursuant to the Top-Up Option would not require approval of the Company’s stockholders under applicable Laws (including, for this purpose the rules and regulations of the Nasdaq Global Select Market), (C) upon exercise of the Top-Up Option, the number of Shares owned by Parent or Merger Sub or any wholly owned Subsidiary of Parent or Merger Sub constitutes 90.0005% of the number of Shares that will be outstanding immediately after the issuance of the Top-Up Option Shares, and (D) the number of Top-Up Option Shares issued pursuant to the Top-Up Option shall in no event exceed the number of authorized and unissued shares of common stock of the Company less the maximum number of shares potentially necessary for issuance with respect to all outstanding Company Options, Company Restricted Stock Units, Company Warrants, the Convertible Notes or other obligations of the Company. The parties shall cooperate to ensure that the issuance of the Top-Up Option Shares is accomplished consistent with all applicable Laws, including compliance with an applicable exemption from registration of the Top-Up Option Shares under the Securities Act. Parent and Merger Sub shall have the right,

but shall not be required to, exercise the Top-Up Option in its sole discretion and may only exercise the Top-Up Option if following its exercise, the condition set forth in clause (C) would be satisfied.

               (b)  Exercise of Top-Up Option . Upon the exercise of the Top-Up Option in accordance with Section 2.4(a) , Parent shall so notify the Company and shall set forth in such notice (i) the number of Shares that are expected to be owned by Parent, Merger Sub or any wholly owned Subsidiary of Parent or Merger Sub immediately preceding the purchase of the Top-Up Option Shares and (ii) a place and time for the closing of the purchase of the Top-Up Option Shares. The Company shall, as soon as practicable following receipt of such notice, notify Parent and Merger Sub of the number of Shares then outstanding and the number of Top-Up Option Shares. At the closing of the purchase of the Top-Up Option Shares, Parent or Merger Sub, as the case may be, shall pay the Company the aggregate price required to be paid for the Top-Up Option Shares, and the Company shall cause to be issued to Parent or Merger Sub, as applicable, a certificate representing the Top-Up Option Shares. The aggregate purchase price payable for the Top-Up Shares may be paid by Merger Sub or Parent in cash or by executing and delivering to the Company a promissory note having a principal amount equal to the balance of the aggregate purchase price for the Top-Up Shares, or some combination thereof. Any such promissory note shall bear interest at a rate of interest per annum equal to 3%, shall mature on the first anniversary of the date of execution and delivery of such promissory note and may be prepaid without premium or penalty. In the event that Merger Sub becomes the owner of 90.0005% or more of the outstanding shares of Common Stock, Parent shall promptly cause Merger Sub to consummate the Merger in accordance with Section 253 of the DGCL.

               (c)  Accredited Investor Status . Parent and Merger Sub acknowledge that the Shares which Merger Sub may acquire upon exercise of the Top-Up Option will not be registered under the Securities Act and will be issued in reliance upon an exemption thereunder for transactions not involving a public offering. Parent and Merger Sub represent and warrant to the Company that Merger Sub is, or will be upon the purchase of the Top-Up Option Shares, an “accredited investor,” as defined in Rule 501 of Regulation D under the Securities Act. Merger Sub agrees that the Top-Up Option and the Top-Up Options Shares to be acquired upon exercise of the Top-Up Option are being and will be acquired by Merger Sub for the purpose of investment and not with a view to, or for resale in connection with, any distribution thereof (within the meaning of the Securities Act).

ARTICLE III
MERGER

     Section 3.1 The Merger . On the terms and subject to the conditions set forth in this Agreement, and in accordance with the DGCL, at the Effective Time, Merger Sub will merge with and into the Company, the separate corporate existence of Merger Sub will cease and the Company will continue its corporate existence under Delaware law as the surviving corporation in the Merger (the “ Surviving Corporation ”) and shall succeed to and assume all the rights and obligations of Merger Sub in accordance with Section 259 of the DGCL.

     Section 3.2 Closing . Unless otherwise mutually agreed in writing by the Company and Merger Sub, the closing of the Merger (the “ Closing ”) will take place at the offices of Kirkland & Ellis LLP, 200 E. Randolph Drive, Chicago, Illinois, at 10:00 a.m. (Central Time) on the second Business Day after the satisfaction or waiver of the conditions set forth in Article IX (excluding conditions that, by their terms, cannot be satisfied until the Closing but subject to the satisfaction or waiver of such conditions at the Closing). The date on which the Closing actually occurs is hereinafter referred to as the “ Closing Date .”

     Section 3.3 Effective Time . Subject to the provisions of this Agreement, at the Closing, the Company will cause a certificate of merger or certificate of ownership and merger, as applicable (the “ Certificate of Merger ”) to be executed, acknowledged and filed with the Secretary of State of the State of Delaware in accordance with the relevant provisions of the DGCL. The Merger will become effective at such time as the Certificate of Merger has been duly filed with the Secretary of State of the State of Delaware or at such later date or time as may be agreed by the Company and Merger Sub in writing and specified in the Certificate of Merger in accordance with the DGCL (the effective time of the Merger being hereinafter referred to as the “ Effective Time ”).

     Section 3.4 Effects of the Merger . The Merger shall have the effects set forth in this Agreement and the applicable provisions of the DGCL. Without limiting the generality of the foregoing, and subject thereto, from and after the Effective Time, all property, rights, privileges, immunities, powers, franchises, licenses and authority of the Company and Merger Sub shall vest in the Surviving Corporation, and all debts, liabilities, obligations, restrictions and duties of each of the Company and Merger Sub shall become the debts, liabilities, obligations, restrictions and duties of the Surviving Corporation.

     Section 3.5 Organizational Documents . At the Effective Time, (a) the Certificate of Incorporation of the Surviving Corporation shall be amended to read in its entirety as set forth on Exhibit I attached hereto, until thereafter amended in accordance herewith and applicable Law, and (b) the bylaws of the Surviving Corporation shall be amended to read as set forth on Exhibit II attached hereto, until thereafter amended in accordance with the certificate of incorporation of the Surviving Corporation, such bylaws and applicable Law.

     Section 3.6 Directors and Officers of Surviving Corporation . The directors of Merger Sub and the officers of the Company (other than those who Parent determines shall not remain as officers of the Surviving Corporation), in each case, immediately prior to the Effective Time shall, from and after the Effective Time, be the directors and officers, respectively, of the Surviving Corporation until their successors have been duly elected or appointed and qualified or until their earlier death, resignation or removal in accordance with the Certificate of Incorporation or bylaws of the Surviving Corporation.

ARTICLE IV
EFFECT OF THE MERGER ON CAPITAL
STOCK

   Section 4.1 Conversion of Securities . At the Effective Time, pursuant to this Agreement and by virtue of the Merger and without any action on the part of the Company, Merger Sub or the holders of the Shares:

          (a) Each share of Common Stock, par value $0.001 per share, of the Company (the “ Common Stock ” or the “ Shares ”) held by the Company as treasury stock or owned directly or indirectly by Parent immediately prior to the Effective Time (whether pursuant to the Offer or otherwise) shall be canceled and retired and shall cease to exist, and no payment or distribution shall be made or delivered with respect thereto.

          (b) Each share of common stock, par value $0.001 per share, of Merger Sub issued and outstanding immediately prior to the Effective Time shall be converted into and become one newly issued, fully paid and non-assessable share of common stock of the Surviving Corporation.

          (c) Each Share issued and outstanding immediately prior to the Effective Time (other than Shares to be canceled pursuant to Section 4.1(a) ), automatically shall be canceled and converted into the right to receive cash in an amount equal to the Offer Price, without interest thereon (the “ Merger Consideration ”), payable to the holder thereof upon surrender of the stock certificate formerly representing such Share (a “ Certificate ”) in the manner provided in Section 4.2 . Such Shares, other than those canceled pursuant to Section 4.1(a) , sometimes are referred to herein as the “ Merger Shares .”

          (d) If between the date of this Agreement and the Effective Time the number of outstanding Shares is changed into a different number of shares or a different class, by reason of any stock dividend, subdivision, reclassification, recapitalization, split-up, combination, exchange of shares or the like, other than pursuant to the Merger, the amount of Merger Consideration payable per Merger Share shall be correspondingly adjusted.

   Section 4.2 Payment of Cash for Merger Shares .

          (a) Prior to the Closing Date, Parent shall (i) designate a bank or trust company that is reasonably satisfactory to the Company (the “ Paying Agent ”) and (ii) enter into a paying agent agreement, in form and substance reasonably satisfactory to the Company, with such Paying Agent, to serve as the Paying Agent for the Merger Consideration. Prior to the filing of the Certificate of Merger with the Secretary of State of the State of Delaware, Parent will deposit with the Paying Agent cash in the aggregate amount sufficient to pay the Merger Consideration in respect of all Merger Shares outstanding immediately prior to the Effective Time. Pending distribution of the cash deposited with the Paying Agent, such cash shall be held in trust for the

benefit of the holders of Merger Shares outstanding immediately prior to the Effective Time, and shall not be used for any other purposes; provided , however , that Parent may direct the Paying Agent to invest such cash in (i) obligations of or guaranteed by the United States of America or any agency or instrumentality thereof, (ii) money market accounts, certificates of deposit, bank repurchase agreement or banker’s acceptances of, or demand deposits with, commercial banks having a combined capital and surplus of at least $1,000,000,000 (based on the most recent financial statements of such bank which are publicly available), or (iii) commercial paper obligations rated P-1 or A-1 or better by Standard & Poor’s Corporation or Moody’s Investor Services, Inc. Any profit or loss resulting from, or interest and other income produced by, such investments shall be for the account of the Surviving Corporation.

          (b) As promptly as practicable after the Effective Time (and in no event later than two Business Days), the Surviving Corporation shall send, or cause the Paying Agent to send, to each record holder of Merger Shares entitled to receive the Merger Consideration a letter of transmittal and instructions for exchanging their Merger Shares for the Merger Consideration payable therefor. The letter of transmittal will be in customary form and will specify that delivery of Certificates (or effective affidavits of loss in lieu thereof) will be effected, and risk of loss and title will pass, only upon delivery of the Certificates (or effective affidavits of loss in lieu thereof) to the Paying Agent. Upon surrender of Certificate or Certificates (or effective affidavits of loss in lieu thereof) to the Paying Agent together with a properly completed and duly executed letter of transmittal and any other documentation that the Paying Agent may reasonably require, the record holder thereof shall be entitled to receive the Merger Consideration payable in exchange therefor. Until so surrendered and exchanged, each such Certificate shall, after the Effective Time, be deemed to represent only the right to receive the Merger Consideration, and until such surrender and exchange, no cash shall be paid to the holder of such outstanding Certificate in respect thereof.

          (c) If payment is to be made to a Person other than the registered holder of the Merger Shares formerly represented by the Certificate or Certificates surrendered in exchange therefor, it shall be a condition to such payment that the Certificate or Certificates so surrendered shall be properly endorsed or otherwise be in proper form for transfer and that the Person requesting such payment shall pay to the Paying Agent any applicable stock transfer taxes required as a result of such payment to a Person other than the registered holder of such Merger Shares or establish to the reasonable satisfaction of the Paying Agent that such stock transfer taxes have been paid or are not payable.

          (d) After the Effective Time, there shall be no further transfers on the stock transfer books of the Company of the Shares that were outstanding immediately prior to the Effective Time other than to settle transfers of Shares that occurred prior to the Effective Time. If, after the Effective Time, Certificates are presented to the Surviving Corporation or the Paying Agent, such shares shall be canceled and exchanged for the consideration provided for, and in accordance with the procedures set forth, in this Article IV .

          (e) If any cash deposited with the Paying Agent remains unclaimed nine months after the Effective Time, such cash and any interest accrued thereon shall be returned to the Surviving Corporation upon demand, and any holder who has not surrendered such holder’s Certificates for the Merger Consideration prior to that time shall thereafter look only to the Surviving Corporation for payment of the Merger Consideration. Notwithstanding the foregoing, none of Merger Sub, the Company, the Surviving Corporation or the Paying Agent shall be liable to any holder of Certificates for any amount paid to a public official pursuant to any applicable unclaimed property laws. Any amounts remaining unclaimed by holders of Certificates as of a date immediately prior to such time that such amounts would otherwise escheat to or become property of any Governmental Authority shall, to the extent permitted by applicable Law, become the property of the Surviving Corporation on such date, free and clear of any claims or interest of any Person previously entitled thereto.

          (f) No dividends or other distributions with respect to capital stock of the Surviving Corporation with a record date after the Effective Time shall be paid to the holder of any unsurrendered Certificate.

          (g) From and after the Effective Time, the holders of Shares outstanding immediately prior to the Effective Time shall cease to have any rights with respect to such Shares, other than the right to receive the Merger Consideration as provided in this Agreement.

          (h) In the event that any Certificate has been lost, stolen or destroyed, upon the making of an affidavit of that fact by the Person claiming such Certificate to be lost, stolen or destroyed, in addition to the posting by such holder of any bond in such reasonable amount as the Surviving Corporation or the Paying Agent may direct as indemnity against any claim that may be made against the Surviving Corporation with respect to such Certificate, the Paying Agent will issue in exchange for such lost, stolen or destroyed Certificate the proper amount of the Merger Consideration in respect thereof entitled to be received pursuant to this Agreement.

          (i) Parent, the Surviving Corporation and the Paying Agent shall be entitled to deduct and withhold from the Merger Consideration otherwise payable hereunder and any amounts to be paid hereunder in respect of Company Options or Company Restricted Stock Units any amounts required to be deducted and withheld under any applicable Tax Law. To the extent any amounts are so withheld, such withheld amounts shall be timely paid to the applicable Tax authority and shall be treated for all purposes as having been paid to the holder from whose Merger Consideration (or amounts payable hereunder with respect to Company Options or Company Restricted Stock Units) the amounts were so deducted and withheld.

   Section 4.3 Treatment of Options, Restricted Stock Units and Other Awards.

          (a) At the Effective Time, by virtue of the Merger and without any action on the part of the holders thereof, each Company Option (whether or not then vested or exercisable) and unvested Company Restricted Stock Unit that is outstanding immediately prior

to the Effective Time shall be assumed by Parent and converted automatically at the Effective Time into an option or restricted stock unit, as the case may be, denominated in shares of Parent Common Stock and which has other terms and conditions substantially identical to those of the related Company Option or Company Restricted Stock Unit, as the case may be (including any accelerated vesting provisions therein), except that (i) the number of shares of Parent Common Stock subject to each such award shall be determined by multiplying the number of shares of Company Common Stock subject to such Company Option or Company Restricted Stock Unit, as the case may be, immediately prior to the Effective Time by a fraction (the “Award Exchange Ratio”), the numerator of which is the Offer Price and the denominator of which is the Parent Closing Value (and rounding such amount up to the nearest share if .5 or above and down to the nearest share if below .5) and (ii) if applicable, the exercise or purchase price per share of Parent Common Stock shall equal (x) the per share exercise price or purchase price for the shares of Company Common Stock otherwise purchasable pursuant to such Company Option or Company Restricted Stock Unit, as applicable, immediately prior to the Effective Time, divided by (y) the Award Exchange Ratio (with such quotient rounded up to the nearest whole cent); provided, however, that if the exchange of a Company Option for a Parent Stock Option is not in compliance with the adjustment requirements of Section 409A of the Code then it shall be cancelled in exchange for a payment equal to the excess (if any) of (A) the product of (I) the number of Shares subject to such Company Option and (II) the Offer Price over (B) the aggregate exercise price of such Company Option, without interest and less any amounts required to be deducted and withheld under any applicable Law. The assumption and adjustment of the Company Options and Company Restricted Stock Units, as applicable, in accordance with this Section 4.3(a) shall preserve the compensation element of each Company Option or Company Restricted Stock Unit, as applicable, as of the Effective Time.

          (b) Each assumed Company Option shall be deemed vested immediately following the Effective Time as to the same percentage of the total number of shares subject thereto as it was vested immediately prior to the Effective Time, except with respect to any Company Option or Company Restricted Stock Unit governed by any of the agreements set forth on Schedule 4.3 of the Company Disclosure Letter which provide for acceleration of vesting by reason of the transactions contemplated hereby. Each assumed Company Option and Company Restricted Stock Unit will otherwise continue to have, and be subject to, substantially identical terms and conditions as in effect immediately prior to the Effective Time. Prior to the Closing, Parent shall take all corporate action necessary to reserve for issuance a sufficient number of shares of Parent Common Stock for delivery upon exercise of Company Options or Company Restricted Stock Units or in connection with any other Company Incentive Plans for which shares of Parent Common Stock are required to be reserved for issuance. No later than 3 Business Days after the Effective Date, Parent shall file a registration statement on Form S-3 or Form S-8, as the case may be (or any successor or other appropriate forms), with respect to the shares of Parent Common Stock subject to such options, restricted stock units or Company Incentive Plans for which registration of shares of Parent Common Stock is required and shall use its reasonable best efforts to maintain the effectiveness of such registration statement or registration statements (and maintain the current status of the prospectus or prospectuses contained therein) for so long as such options or restricted stock units remain outstanding or for so long as such registration statement is required with respect to any other Company Incentive Plans. As soon as reasonably practicable after the Effective Time, Parent shall deliver to each holder of any Company Option or unvested Company Restricted Stock Unit

an appropriate notice setting forth such holder’s rights pursuant to such Company Option or unvested Company Restricted Stock Unit, as applicable. The parties agree to apply the ‘Next day rule’ of Treasury Regulation Sec. 1.1502-76(b)(1)(ii)(B) with respect to the Company’s stock option deduction for tax purposes.

          (c) At the Effective Time, by virtue of the Merger and without any action on the part of the holders thereof, each then outstanding Company Restricted Stock Unit that (i) has become vested on or before the Closing by its written terms as set forth in the relevant award agreement as in effect on the date hereof (or as the same may be modified by any Employment Agreement between the recipient and the Company in effect on the date hereof) and (ii) has not been settled as of the Closing Date shall be converted into the right to receive the Merger Consideration. At the Effective Time, by virtue of the Merger and without any action on the part of the holders thereof, each such vested Company Restricted Stock Unit shall cease to be outstanding and shall be canceled, and any award agreement (or portion thereof) evidencing the grant of any such Company Restricted Stock Unit shall thereafter represent only the right to receive the Merger Consideration with respect to the Company Restricted Stock Units formerly represented thereby.

          (d) On the Revised Exercise Date, all amounts withheld by the Company on behalf of the participants in the Company’s 2000 Employee Stock Purchase Plan (the “Stock Purchase Plan”) from the beginning of the applicable existing salary reduction periods through the Revised Exercise Date will be deemed to have been used to purchase Common Stock pursuant to the terms of the Stock Purchase Plan, using the Revised Exercise Date as the last date of the salary reduction period under the Stock Purchase Plan, unless prior to the Revised Exercise Date the participant in question has withdrawn from the offering period pursuant to the provisions of the Stock Purchase Plan. As of the Effective Time, each such share of Common Stock will be cancelled and converted into the right to receive the Merger Consideration as provided in Section 4.1. On or after the date of this Agreement, in no event (x) shall any person who is not currently participating in the Stock Purchase Plan be permitted to begin participating in the Stock Purchase Plan, and (y) shall any person who is currently participating in the Stock Purchase Plan be permitted to increase the level of salary reduction amount that may otherwise be deemed used to purchase shares of Common Stock under the Stock Purchase Plan from that level of salary reduction amount in effect as of the date of this Agreement; and provided, further, that in no event may any new offering period commence after the date hereof and prior to the Revised Exercise Date.

     Section 4.4 Dissenting Shares . Notwithstanding anything in this Agreement to the contrary, Shares issued and outstanding immediately prior to the Effective Time that are held by any holder who has not voted in favor of the Merger and who is entitled to demand and properly demands, exercises, and perfects his or her demand for appraisal of such Shares pursuant to Section 262 of the DGCL (“ Dissenting Shares ”), shall not be converted into the right to receive the Merger Consideration, unless and until such holder shall have effectively withdrawn or lost, such holder’s right to appraisal under the DGCL. Dissenting Shares shall be treated in accordance with Section 262 of the DGCL and shall be entitled to receive consideration thereunder . If any such holder fails to perfect or withdraws or loses any such right to appraisal, each such Share of such holder shall thereupon be converted into and become exchangeable only for the right to receive, as of the later of the Effective Time and the time that such right to

appraisal has been irrevocably lost, withdrawn or expired, the Merger Consideration in accordance with Section 4.1(c). The Company shall give Parent (i) prompt notice of any written demands for appraisal of any Shares, attempted withdrawals of such demands and any other instruments served pursuant to Section 262 of the DGCL and received by the Company relating to rights of appraisal and (ii) the opportunity to direct all negotiations and proceedings with respect to demands for appraisal under the DGCL. Except with the prior written consent of Parent, the Company shall not make any payment with respect to any demands for appraisal or settle or offer to settle any such demands for appraisal.

     Section 4.5 Further Assurances. After the Effective Time, the officers and directors of the Surviving Corporation will be authorized to execute and deliver, in the name and on behalf of the Company or Parent, any deeds, bills of sale, assignments or assurances and to take and do, in the name and on behalf of the Company or Parent, any other actions and things to vest, perfect or confirm of record or otherwise in the Surviving Corporation any and all right, title and interest in, to and under any of the rights, properties or assets acquired or to be acquired by the Surviving Corporation as a result of, or in connection with, the Offer or the Merger.

ARTICLE V
REPRESENTATIONS AND WARRANTIES OF THE COMPANY

     Except as set forth in the corresponding sections or subsections of the disclosure letter delivered to Parent by the Company concurrently with entering into this Agreement (the “ Company Disclosure Letter ”) (it being agreed that disclosure of any item in any section or subsection of the Company Disclosure Letter shall be deemed to be disclosed with respect to any other section or subsection to which the relevance of such disclosure is readily apparent) or as may be disclosed in the Company SEC Reports filed on or after December 31, 2006 and prior to the date of this Agreement (excluding only matters disclosed in “risk factors” or the “forward-looking statements” disclaimer), the Company hereby represents and warrants to Parent and Merger Sub as follows:

     Section 5.1 Corporate Existence and Power . The Company and each of its Subsidiaries is duly organized, validly existing and in good standing under the laws of its jurisdiction of organization (with respect to jurisdictions that recognize the concept of good standing) except in the case of the Company’s Subsidiaries, where the failure to be so organized, existing and in good standing has not had, and would not reasonably be expected to have, individually or in the aggregate, a Material Adverse Effect on the Company. The Company and each of its Subsidiaries has all corporate or similar powers and authority required to own, lease and operate its respective properties and to carry on its business as now conducted, except in the case of the Company’s Subsidiaries, where the failure to have such power and authority has not had, and would not reasonably be expected to have, individually or in the aggregate, a Material Adverse Effect on the Company. The Company and each of its Subsidiaries is duly licensed or qualified to do business in each jurisdiction in which the nature of the business conducted by it or the character or location of the properties and assets owned or leased by it makes such qualification necessary, except where the failure to be so licensed or qualified has not had, and would not reasonably be expected to have, individually or in the aggregate, a Material Adverse Effect on the Company. None of the Company or its Subsidiaries is in violation of its organizational or governing documents in any material respect. The Company has heretofore

made available to Parent and Merger Sub true and complete copies of the certificate of incorporation and bylaws of the Company as currently in effect.

     Section 5.2 Corporate Authorization.

          (a) The Company has the corporate power and authority to execute and deliver this Agreement and, subject to the adoption of this Agreement by the affirmative vote of the holders of a majority of the outstanding shares of Common Stock if required pursuant to the DGCL or the rules of the Nasdaq Global Select Market (the “ Requisite Stockholder Vote ”), to consummate the Merger and the other transactions contemplated hereby and to perform each of its obligations hereunder. The execution, delivery and performance by the Company of this Agreement and the consummation by the Company of the Offer, the Merger and the other transactions contemplated hereby have been duly and validly authorized by the Board of Directors of the Company. Except for the adoption of this Agreement by the Requisite Stockholder Vote if required pursuant to the DGCL, no other corporate proceedings on the part of the Company are necessary to approve this Agreement or to consummate the Offer, the Merger or the other transactions contemplated hereby. At a duly held meeting, the Board of Directors of the Company has unanimously (i) determined that it is in the best interests of the Company and its stockholders, and declared it advisable, to enter into this Agreement, (ii) approved the execution, delivery and performance of this Agreement and the consummation of the transactions contemplated hereby, including the Offer and the Merger, and (iii) subject to the provisions of Section 8.6 , resolved to recommend that the Company Stockholders approve the adoption of this Agreement and directed that such matter be submitted for consideration of the stockholders of the Company at the Company Stockholder Meeting.

          (b) This Agreement has been duly and validly executed and delivered by the Company and, assuming the due and valid execution and delivery of this Agreement by Parent and Merger Sub, constitutes a legal, valid and binding agreement of the Company enforceable against the Company in accordance with its terms, except as such enforceability may be limited by bankruptcy, insolvency, moratorium, reorganization or similar Laws affecting the enforcement of creditors’ rights generally and general equitable principles (the “ Bankruptcy and Equity Exception ”).

     Section 5.3 Governmental Authorization . The execution, delivery and performance by the Company of this Agreement and the consummation by the Company of the Offer and the Merger do not and will not require any consent, approval, authorization or permit of, action by, filing with or notification to any Governmental Authority, other than (i) the filing of the Certificate of Merger; (ii) compliance with the applicable requirements of any Regulatory Law; (iii) the applicable requirements of the Exchange Act including the filing of the Schedule 14D-9 and the Company Proxy Statement; (iv) compliance with the rules and regulations of the Nasdaq Global Select Market; (v) compliance with any applicable state securities or blue sky laws; and (vi) any such consent, approval, authorization, permit, action, filing or notification the failure of which to make or obtain would not (A) individually or in the aggregate, reasonably be expected to have a Material Adverse Effect on the Company or (B) reasonably be expected to prevent or materially delay the consummation of the Offer or the Merger.

     Section 5.4 Non-Contravention . Except as set forth in Section 5.4 of the Company Disclosure Letter, the execution, delivery and performance by the Company of this Agreement and the consummation by the Company of the Merger and the other transactions contemplated hereby do not and will not (i) contravene or conflict with, or result in any violation or breach of any provision of, the organizational or governing documents of (A) the Company or (B) any of its Subsidiaries; (ii) assuming compliance with the matters referenced in Section 5.3 and the receipt of the Requisite Stockholder Vote, contravene or conflict with or constitute a violation of any provision of any Law binding upon or applicable to the Company or any of its Subsidiaries or any of their respective properties or assets; or (iii) require the consent, approval or authorization of, or notice to or filing with any third party with respect to, or result in any breach or violation of, or constitute a default (or an event which with notice or lapse of time or both would become a default) or result in the loss of benefit under, or give rise to any right of termination, cancellation, amendment or acceleration of, any right or obligation of the Company or any of its Subsidiaries, or result in the creation of any Lien (other than Permitted Liens) on any of the properties or assets of the Company or any of its Subsidiaries under any loan or credit agreement, note, bond, mortgage, indenture, contract, agreement, Real Property Lease, license, permit or other instrument or obligation (each, a “ Contract ”) to which the Company or any of its Subsidiaries is a party or by which the Company or any of its Subsidiaries or its or any of their respective properties or assets are bound, except in the case of clauses (ii) and (iii) above, which would not (A) individually or in the aggregate, reasonably be expected to have a Material Adverse Effect on the Company or (B) reasonably be expected to prevent or materially delay the consummation of the Merger.

     Section 5.5 Capitalization .

          (a) As of the date hereof, the authorized capital stock of the Company consists of 100,000,000 shares of Common Stock and 10,000,000 shares of Participating Preferred Stock, par value $0.001 per share (the “ Preferred Stock ”) of which 100,000 of such shares are designated as Series A Participating Preferred Stock, par value $0.001, and have been reserved for issuance upon the exercise of the rights (the “ Company Rights ”) distributed to the holders of Common Stock pursuant to the Company’s Preferred Stock Rights Agreement by and between the Company and Computershare Investor Services (f/k/a Equiserve Trust Company NA), dated as of October 24, 2001, as amended (the “ Company Rights Plan ”).

          (b) As of June 4, 2008, the issued and outstanding capital stock of the Company consisted of 44,328,663 shares of Common Stock (excluding shares held in the treasury of the Company as described in clause (ii) below), all of which were validly issued, fully paid and nonassessable and free of preemptive rights;

               (i) As of June 4, 2008, no shares of Preferred Stock were issued and outstanding;

               (ii) As of June 4, 2008, 218,000 shares of Common Stock were held in the treasury of the Company;

               (iii) As of the date hereof, no Common Stock is owned by any of the Company’s Subsidiaries;

               (iv) As of June 4, 2008, 9,303,891 shares of Common Stock were reserved for issuance as awards under the Company’s Incentive Plans, of which 5,894,904 shares were subject to outstanding Company Options and 832,298 shares were subject to existing Company Restricted Stock Units and 2,576,689 were available for future issuance;

               (v) As of June 4, 2008, 397,632 shares of Common Stock were reserved for future issuance under the Stock Purchase Plan;

               (vi) As of June 4, 2008, 1,815,000 shares of Common Stock were reserved for future issuance under Company Warrants;

               (vii) As of June 4, 2008, 2,480,313 shares of Common Stock were reserved for issuance upon conversion of the Convertible Notes;

               (viii) As of June 4, 2008, 40,000 shares of TWT Japan common stock were issued and outstanding of which 40,000 shares were owned by the Company;

               (ix) As of June 4, 2008, 15,168 shares of TWT Japan preferred stock were issued and outstanding, none of which were owned by the Company;

               (x) As of June 4, 2008, 2,388 shares of TWT Japan common stock were reserved for future issuance under the TWT Japan Warrants, none of which were owned by the Company; and

               (xi) As of June 4, 2008, all of the outstanding shares of the capital stock of Third Wave AgBio, Inc. were owned by the Company.

          (c) Except as set forth in Section 5.5(c) of the Company Disclosure Letter and except as provided in Section 5.5(b) , there are no outstanding: (i) shares of capital stock or other voting securities of the Company; (ii) securities of the Company or any of its Subsidiaries convertible into or exchangeable for shares of capital stock or voting securities of the Company or any of its Subsidiaries; (iii) Company Options or other rights or options to acquire from the Company or any of its Subsidiaries, or obligations of the Company or any of its Subsidiaries to issue, any shares of capital stock, voting securities or securities convertible into or exchangeable for shares of capital stock or voting securities of the Company or such Subsidiary, as the case may be (other than the Top-Up Shares); or (iv) equity equivalent interests in the ownership or earnings of the Company or any of its Subsidiaries or other similar rights (the items in clauses (i) through (iv) collectively, “ Company Securities ”). Except as provided in Section 5.5(c) of the Company Disclosure Letter, there are no outstanding obligations of the Company or any of its Subsidiaries to repurchase, redeem or otherwise acquire any Company Securities. Except as provided in Section 5.5(c) of the Company Disclosure Letter, there are no preemptive rights of any kind which obligate the Company or any of its Subsidiaries to issue or deliver any Company Securities. Except as provided in Section 5.5(c) of the Company Disclosure Letter, there are no stockholder agreements, voting trusts or other agreements or understandings to which the Company or any of its Subsidiaries is a party or by which it is bound relating to the voting or registration of any shares of capital stock of the Company or any of its Subsidiaries or preemptive rights with respect thereto.

          (d) The Company has not declared or paid any dividend or distribution in respect of any Company Securities issued by the Company and neither the Company nor any of its Subsidiaries has issued, sold, repurchased, redeemed or otherwise acquired any Company Securities issued by the Company other than the issuance of shares upon the exercise of Company Options, Company Restricted Stock Units, Company Warrants and/or the conversion of the Convertible Notes or in connection with the net exercise thereof in accordance with their terms or the withholding of the foregoing to satisfy Tax obligations and their respective Boards of Directors have not authorized any of the foregoing.

          (e) Except as set forth in Section 5.5(e) of the Company Disclosure Letter, neither the Company nor any of its Subsidiaries has entered into any commitment, arrangement or agreement, or are otherwise obligated, to contribute capital, loan money or otherwise provide funds or make additional investments in any other Person, other than Intercompany Debt.

          (f) No bonds, debentures, notes or other indebtedness having the right to vote generally on any matters on which stockholders of the Company may vote are outstanding.

          (g) Except as provided in the Agreements set forth in Section 5.5(g) of the Company Disclosure Letter, no acceleration of vesting, continuation of vesting after termination of employment or other special vesting (whether with the passage of time, upon the occurrence of certain events or otherwise) will occur, result from or be related to the transactions contemplated by this Agreement.

     Section 5.6 Company Subsidiaries .

          (a) Section 5.6(a) of the Company Disclosure Letter sets forth a list of all the Company’s Subsidiaries.

          (b) All equity interests of any Subsidiary held by the Company or any other Subsidiary are validly issued, fully paid and non-assessable and were not issued in violation of any preemptive or similar rights, purchase option, call, or right of first refusal or similar rights. Except as set forth in Section 5.6(b) of the Company Disclosure Letter, all such equity interests are free and clear of any Liens or any other limitations or restrictions on such equity interests (including any limitation or restriction on the right to vote, pledge or sell or otherwise dispose of such equity interests) other than Permitted Liens. The Company has made available to Parent or its employees, consultants, agents, advisors, affiliates or other representatives true, correct and complete copies of the organizational or governing documents of the Company’s Subsidiaries and a true, correct and complete list of the stockholders of TWT Japan, indicating the number of shares held by each such stockholder.

     Section 5.7 Reports and Financial Statements .

          (a) The Company has filed all forms, reports, statements, certifications and other documents (including all exhibits, amendments and supplements thereto) required to

be filed by it with the SEC pursuant to the Securities Act, the Exchange Act or other applicable United States federal securities Laws since January 1, 2006 (all such forms, reports, statements, certificates and other documents (including all exhibits thereto) filed since January 1, 2006, with any amendments and supplements thereto, collectively, the “ Company SEC Reports ”), each of which, including any financial statements or schedules included therein, as finally amended prior to the date of this Agreement, has complied as to form in all material respects with the applicable requirements of the Securities Act and Exchange Act as of the date filed with the SEC. None of the Company’s Subsidiaries is required to file periodic reports with the SEC. None of the Company SEC Reports when filed with the SEC and, if amended, as of the date of such amendment, contained any untrue statement of a material fact or omitted to state a material fact necessary to be stated therein in order to make the statements therein, in the light of the circumstances under which they were made, not misleading, except that no representation is made by the Company with respect to information supplied by Parent, Merger Sub or any of their Affiliates.

          (b) The audited consolidated financial statements of the Company included in the Company SEC Reports on Form 10-K along with the reports thereon by Grant Thornton LLP, the independent auditors of the Company and the unaudited financial statements of the Company included in the Company’s SEC Reports on Form 10-Q (collectively, the “ Company Financial Statements ”), fairly present (subject, in the case of the unaudited statements, to the absence of notes and normal year-end audit adjustments as permitted by the rules related to Quarterly Reports on Form 10-Q promulgated under the Exchange Act, including Regulation S-X), in all material respects, the results of the consolidated operations and changes in stockholders’ equity and cash flows and consolidated financial position of the Company and its Subsidiaries for the respective fiscal periods or as of the respective dates therein set forth. Each of the Company Financial Statements complies in all material respects with applicable accounting requirements and with the published rules and regulations of the SEC with respect thereto, including Regulation S-X and each of such financial statements (including the related notes and schedules, where applicable) were prepared in accordance with GAAP consistently applied during the periods involved, except in each case as indicated in such statements or in the notes thereto or, in the case of unaudited statements, as permitted by the rules related to Quarterly Reports on Form 10-Q promulgated under the Exchange Act, including Regulation S-X.

          (c) The management of the Company has implemented and maintains disclosure controls and procedures (as defined in Rule 13a-15(e) of the Exchange Act) designed to ensure that information relating to the Company, including its consolidated Subsidiaries, required to be disclosed by the Company in the reports that it files or submits under the Exchange Act is recorded, and reported within the time periods specified in the rules and forms of the SEC and that such information is accumulated and communicated to the Company’s management as appropriate to allow timely decisions regarding required disclosure.

          (d) The Company has established and maintained a system of internal control over financial reporting (as defined in Rule 13a-15 and Rule 15(d)-15(f) under the 1934 Act) (“ internal controls ”) sufficient to provide reasonable assurance regarding the reliability of the Company’s financial reporting and the preparation of the Company’s financial statements for external purposes in accordance with GAAP. The Company has disclosed, based on its most

recent evaluation of internal controls prior to the date hereof, to its auditors and audit committee (x) any significant deficiencies and material weaknesses in the design or operation of internal controls which would reasonably be expected to adversely affect the Company’s ability to record, process, summarize and report financial information and (y) any fraud, whether or not material, that involves management or other employees who have a significant role in internal controls.

          (e) There are no outstanding loans or other extensions of credit made by the Company or any of its Subsidiaries to any executive officer (as defined in Rule 3b-7 under the Exchange Act) or director of the Company. The Company has not, since the enactment of the Sarbanes-Oxley Act, taken any action prohibited by Section 402 of the Sarbanes-Oxley Act.

          (f) Each of the principal executive officer of the Company and the principal financial officer of the Company (or each former principal executive officer of the Company and each former principal financial officer of the Company, as applicable) has made all certifications required by Rule 13a-14 or 15d-14 under the 1934 Act and Sections 302 and 906 of the Sarbanes-Oxley Act with respect to the Company SEC Reports, and the statements contained in such certifications are true and accurate. For purposes of this Agreement, “principal executive officer” and “principal financial officer” shall have the meanings given to such terms in the Sarbanes-Oxley Act.

     Section 5.8 Absence of Certain Changes or Events . Since December 31, 2007 to the date of this Agreement, except as otherwise contemplated or permitted by this Agreement, (i) there has not been any event, state of facts, circumstance, development, change, effect or occurrence that, individually or in the aggregate, has had or would reasonably be expected to have a Material Adverse Effect on the Company, (ii) the businesses of the Company and its Subsidiaries have been carried on in all material respects in the ordinary course of business, (iii) except as set forth on Section 5.8 of the Company Disclosure Letter, neither the Company nor any of its Subsidiaries has taken any of the actions requiring the prior written consent of Parent as set forth in Section 7.1 , and (iv) there has not been ;

          (i) any material labor dispute, other than routine individual grievances, or any activity or proceeding by a labor union or representative thereof to organize any employees of the Company or any of its Subsidiaries, which employees were not subject to a collective bargaining agreement as of December 31, 2007, or any material lockouts, strikes, slowdowns, work stoppages or threats thereof by or with respect to such employees; or

          (ii) any damage, de