EXHIBIT 10.17

                               THIRD AMENDMENT TO

                    OPTION AGREEMENT AND ESCROW INSTRUCTIONS

        This THIRD AMENDMENT TO OPTION AGREEMENT AND ESCROW INSTRUCTIONS
("AMENDMENT") is made and effective as of September 27, 2001 ("EFFECTIVE DATE"),
by DIVERSIFIED EASTGATE VENTURE, an Illinois general partnership ("SELLER"), and
ILLUMINA, INC., a Delaware corporation ("BUYER"), with reference to the facts
set forth below.

                                R E C I T A L S:

        A. Pursuant to that certain Option Agreement and Escrow Instructions
dated July 6, 2000, as amended by that certain First Amendment to Option
Agreement and Escrow Instructions dated May 25, 2001 ("FIRST AMENDMENT") and
that certain Second Amendment to Option Agreement and Escrow Instructions dated
July 18, 2001 ("SECOND AMENDMENT") (collectively, "OPTION AGREEMENT"), Seller
granted to Buyer an option ("OPTION") to purchase certain real property located
in the County of San Diego, California, as more particularly described therein
("PROPERTY"). On or about November 30, 2000, Buyer exercised its Option to
purchase the Property.

        B. Seller and Buyer have also entered into that certain Eastgate Pointe
Lease dated July 6, 2000, as amended by that certain First Amendment to Eastgate
Pointe Lease dated concurrently herewith (collectively, "LEASE") whereby Seller,
as Landlord, leased the Property to Buyer, as Tenant.

        C. Pursuant to the First Amendment, the parties agreed to certain
modifications to the Option Agreement and the Lease based upon Buyer's request
for certain additions and modifications to (a) the Project Plans and the Project
Work under the Option Agreement, and (b) the Tenant Improvement Plans and the
Tenant Improvements under the Lease.

        D. As a result of the modifications agreed to in the First Amendment,
the parties acknowledged that Buyer would not be in a position to close Escrow
on or before the outside Closing Date of August 1, 2001. Accordingly, the
parties entered into the Second Amendment to extend the Close of Escrow until
October 1, 2001. In connection with the extension of the Close of Escrow, the
parties also amended the Option Agreement to provide for certain modifications
to the economic terms of the transaction, as set forth therein.

        E. The parties now desire to enter into this Amendment to further extend
the Close of Escrow and to memorialize certain additional modifications to the
Option Agreement, on the terms and conditions set forth herein.

        NOW THEREFORE, in consideration of the foregoing recitals, and for other
good and valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties agree as set forth below.

        1. Section 2.1 -- Credit Against Purchase Price. The first sentence of
Section 2.1 of the Option Agreement shall be modified to add the following at
the end of such sentence:




        ", minus (e) the total amount of Monthly Base Rent (as defined in the
        Lease) paid by Buyer under the Lease prior to the Close of Escrow."

        2. Section 3.4 - Extension of Closing Date. The last sentence of Section
3.4 of the Option Agreement shall be deleted and replaced with the following:
"Escrow shall close on or before January 15, 2002, but in no event earlier than
January 2, 2002 ("CLOSING DATE")".

        3. Payment for Costs Related to Loan Modifications. The parties
acknowledge that Buyer has requested Seller to negotiate certain modifications
to the loan ("Loan") made to Seller by Washington Capital Joint Master Trust
Fund ("Lender"). Such modifications include, without limitation (a) extension of
the "Construction Maturity Date" under the Promissory Note dated September 26,
2000 ("Promissory Note") until on or about January 15, 2002, (b) increase in the
loan principal by an amount equal to Two Million Dollars ($2,000,000) upon
conversion of the construction loan to a permanent loan under the Promissory
Note, and (c) modifications to the interest rate for the "Permanent Loan" under
the Promissory Note (all modifications to be collectively referred to as the
"Loan Modifications"). Buyer agrees that, in consideration of Seller negotiating
the Loan Modifications with Lender and agreeing to be bound by such
modifications as the borrower under the Loan, Buyer shall pay all costs and
expenses incurred in connection with the Loan Modifications. Such costs and
expenses include, without limitation, any and all fees and/or costs imposed by
Lender, appraisal fees, title and escrow fees, recording charges, loan fees and
legal costs incurred by Lender. Notwithstanding the foregoing, Buyer shall not
be obligated to pay to Lender the extension fee imposed by Lender in the amount
of Eighteen Thousand Dollars ($18,000).

        4. Amendment. Except as expressly amended or modified by the provisions
and conditions of this Amendment, the Option Agreement shall remain in full
force and effect.

        5. Defined Terms. Capitalized Terms which are not otherwise defined
herein shall have the meanings attributed to them in Option Agreement.

        6. Counterparts. This Amendment may be executed in counterparts.



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        IN WITNESS WHEREOF, the parties have executed this Amendment as of the
date set forth above.

        SELLER:                  DIVERSIFIED EASTGATE VENTURE,
                                 an Illinois general partnership

                                 By:    Diversified Eastgate Pointe, LLC,
                                        a California limited liability company,
                                        Its General Partner

                                        By:    /s/ WILLIAM P. TSCHANTZ
                                               --------------------------------
                                               Its:  Manager

                                 By:    GFBP Partners, LLC,
                                        a California limited liability company,
                                        Its General Partner

                                        By:    /s/ WILLIAM P. TSCHANTZ
                                               --------------------------------
                                               Its:  Manager

        BUYER:                   ILLUMINA, INC.,
                                 a Delaware corporation

                                 By:    /s/ TIMOTHY M. KISH
                                        ---------------------------------------
                                 Name:  Timothy M. Kish
                                 Title: Vice President & Chief Financial Officer


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                                CONSENT OF LENDER

        The undersigned, as "Lender" under that certain Construction Loan
Agreement dated September 26, 2000, hereby consents to the terms and conditions
of the foregoing Third Amendment to Option Agreement and Escrow Instructions.

Date:  September 27, 2001            WASHINGTON CAPITAL JOINT MASTER
                                     TRUST MORTGAGE INCOME FUND

                                     By:  Washington Capital Management, Inc.,
                                          a Washington corporation,
                                          Its Investment Manager


                                          By:    /s/ DONALD R. MAESCHER
                                                 ------------------------------
                                          Name:  Donald R. Maescher
                                          Title: President, California Division





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