ASSIGNMENT, ASSUMPTION AND RECOGNITION AGREEMENT

Exhibit 99.13(a)

EXECUTION COPY


ASSIGNMENT, ASSUMPTION AND RECOGNITION AGREEMENT

THIS ASSIGNMENT, ASSUMPTION AND RECOGNITION AGREEMENT (this
"Assignment"), dated as of April 1, 2006, is entered into among Morgan Stanley
Capital I Inc., a Delaware corporation (the "Depositor"), Morgan Stanley
Mortgage Capital Inc. ("MSMCI") and MortgageIT, Inc., as seller (the
"Seller"), and acknowledged by LaSalle Bank National Association, as trustee
(the "Trustee") of Morgan Stanley Mortgage Loan Trust 2006-6AR (the "Trust").

RECITALS

WHEREAS MSMCI and the Seller have entered into a certain Amended and
Restated Mortgage Loan Purchase And Warranties Agreement, dated as of May 1,
2005 (the "May Purchase Agreement") and a certain Fourth Amended and Restated
Mortgage Loan Purchase and Warranties Agreement, dated as of March 1, 2006
(the "March Purchase Agreement" and together with the May Agreement, the
"Purchase Agreements"), pursuant to which MSMCI has acquired certain Mortgage
Loans;

WHEREAS, in connection with the transfer of the Mortgage Loans
hereunder, the Seller agrees that, from and after the date hereof, each
Mortgage Loan transferred hereunder will be subject to the March Purchase
Agreement;

WHEREAS the Depositor has agreed, on the terms and conditions
contained herein, to purchase from MSMCI certain of the Mortgage Loans (the
"Specified Mortgage Loans") which are subject to the provisions of the
Purchase Agreements and are listed on the mortgage loan schedule attached as
Exhibit I hereto (the "Specified Mortgage Loan Schedule"); and

WHEREAS the Trustee, on behalf of the Trust, has agreed, on the terms
and conditions contained herein, to purchase from the Depositor the Specified
Mortgage Loans;

NOW, THEREFORE, in consideration of the mutual promises contained
herein and other good and valuable consideration (the receipt and sufficiency
of which are hereby acknowledged), the parties agree as follows:

1. Assignment and Assumption

(a) On and of the date hereof, MSMCI hereby sells, assigns and
transfers to the Depositor all of its right, title and interest in the
Specified Mortgage Loans and all rights and obligations related thereto as
provided under the Purchase Agreements to the extent relating to the Specified
Mortgage Loans, the Depositor hereby accepts such assignment from MSMCI (the
"First Assignment and Assumption"), and the Seller hereby acknowledges the
First Assignment and Assumption.

MSMCI specifically reserves and does not assign to the
Depositor hereunder any and all right, title and interest in, to and under and
all obligations of MSMCI with respect to any Mortgage Loans subject to the
Purchase Agreements which are not the Specified Mortgage Loans.

(b) On and of the date hereof, immediately after giving effect to the
First Assignment and Assumption, the Depositor hereby sells, assigns and
transfers to the Trustee, on behalf of the Trust, all of its right, title and
interest in the Specified Mortgage Loans and all rights and obligations
related thereto as provided under the Purchase Agreements to the extent
relating to the Specified Mortgage Loans, and the Trustee, on behalf of the
Trust, hereby accepts such assignment from the Depositor (the "Second



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Assignment and Assumption"), and the Seller hereby acknowledges the Second
Assignment and Assumption.

(c) On and as of the date hereof, MSMCI represents and warrants to
the Depositor and the Trustee that MSMCI has not taken any action that would
serve to impair or encumber the respective ownership interests of the
Depositor and the Trustee in the Specified Mortgage Loans since the date of
MSMCI's acquisition of the Specified Mortgage Loans.

2. Recognition of Trustee

(a) From and after the date hereof, both MSMCI and the Seller shall
note the transfer of the Specified Mortgage Loans to the Trustee, in their
respective books and records and shall recognize the Trustee, on behalf of the
Trust, as of the date hereof, as the owner of the Specified Mortgage Loans. It
is the intention of the Seller, the Depositor, the Trustee and MSMCI that this
Assignment shall be binding upon and inure to the benefit of the Depositor,
the Trustee and MSMCI and their respective successors and assigns.

(b) Without in any way limiting the foregoing, the parties confirm
that this Assignment includes the rights relating to amendments or waivers
under the Purchase Agreements. Accordingly, the right of MSMCI to consent to
any amendment of the Purchase Agreements and its rights concerning waivers as
set forth in Section 23 of the March Purchase Agreement shall be exercisable,
to the extent any such amendment or waiver affects the Specified Mortgage
Loans or any of the rights under the Purchase Agreements with respect thereto,
solely by the Trustee as assignee of MSMCI.

(c) It is expressly understood and agreed by the parties hereto that
(i) this Assignment is executed and delivered by LaSalle Bank National
Association, not individually or personally but solely on behalf of the Trust,
as the assignee, in the exercise of the powers and authority conferred and
vested in it, as Trustee, pursuant to the Pooling and Servicing Agreement
dated as of the date hereof (the "Pooling and Servicing Agreement") among the
Depositor, Wells Fargo Bank, National Association, as securities administrator
(the "Securities Administrator") and master servicer (the "Master Servicer"),
and the Trustee, (ii) each of the representations, undertakings and agreements
herein made on the part of assignee is made and intended not as personal
representations, undertakings and agreements by LaSalle Bank National
Association but is made and intended for the purpose of binding only the
Trust, (iii) nothing herein contained shall be construed as creating any
liability for LaSalle Bank National Association, individually or personally,
to perform any covenant (either express or implied) contained herein, (iv)
under no circumstances shall LaSalle Bank National Association be personally
liable for the payment of any indebtedness or expenses of the Trust, or be
liable for the breach or failure of any obligation, representation, warranty
or covenant made or undertaken by the Trust under this Assignment and (v) all
recourse for any payment liability or other obligation of the assignee shall
be had solely to the assets of the Trust.

3. Representations and Warranties

(a) The Depositor represents and warrants that it is a sophisticated
investor able to evaluate the risks and merits of the transactions
contemplated hereby, and that it has not relied in connection therewith upon
any statements or representations of the Seller or MSMCI other than those
contained in the Purchase Agreements or this Assignment.

(b) Each of the parties hereto represents and warrants that it is
duly and legally authorized to enter into this Assignment.



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(c) Each of the Depositor, MSMCI and the Seller represents and
warrants that this Assignment has been duly authorized, executed and delivered
by it and (assuming due authorization, execution and delivery thereof by each
of the other parties hereto) constitutes its legal, valid and binding
obligation, enforceable against it in accordance with its terms, except as
such enforcement may be limited by bankruptcy, insolvency, reorganization or
other similar laws affecting the enforcement of creditors' rights generally
and by general equitable pr