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EXHIBIT 10.16



                                 March 27, 2000



Motorola, Inc.
4088 Commercial Drive
Northbrook, IL  60062

                         Common Stock Purchase Agreement
Ladies and Gentlemen:

         The purpose of this letter (the "Agreement") is to confirm in writing
the agreement of Motorola, Inc. ("Motorola") to purchase shares of Common Stock
of Genometrix Incorporated ("Genometrix"), a Delaware corporation, pursuant to
the terms set forth herein.

         Motorola is currently the record and beneficial owner of 706,714 shares
of Genometrix Series D Convertible Preferred Stock and 2,666,667 shares of
Genometrix Series E Convertible Preferred Stock, which are convertible
automatically into shares of Common Stock of Genometrix upon the completion of a
qualified initial public offering by Genometrix, into an aggregate of 3,373,381
shares of Common Stock (collectively, "Motorola Common Stock Equivalents").
Reference is made to the Stock Purchase Agreement (the "Series D Agreement")
dated December 28, 1998 and the Series E Stock Purchase Agreement (the "Series E
Agreement") dated as of July 6, 1999, each entered into by and between
Genometrix Incorporated, now a wholly-owned subsidiary of Genometrix and
currently known as Genometrix Genomics Incorporated ("Genometrix Sub"), and
Motorola and the First Amended and Restated Registration Rights Agreement
("Registration Rights Agreement") dated as of July 6, 1999, entered into by and
between Genometrix Sub and Motorola. Genometrix and Motorola agree that
Genometrix shall hereby become a party to the Series D Agreement, the Series E
Agreement and the Registration Rights Agreement and shall, effective
immediately, have all the obligations and rights of Genometrix Sub as set forth
in each such agreement.

         On March 15, 2000, Genometrix filed with the United States Securities
and Exchange Commission ("SEC") a Registration Statement on Form S-1
("Registration Statement") (No. 333-32584) with respect to an initial public
offering of shares of its Common Stock (the "Genometrix IPO"). Motorola
acknowledges that it has received a copy of the Genometrix Form S-1, without
exhibits, that it has access to the Registration Statement, with exhibits, over
the Internet, and that it has had access to such officers of, and information
from, Genometrix as it deems prudent. Genometrix has advised Motorola that the
Genometrix IPO is contemplated to be underwritten by Lehman Brothers and Chase
H&Q as co-managing underwriters and Dain Rauscher Wessels and Thomas Weisel
Partners as co-underwriters (collectively, the "Underwriters").
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         Contemporaneously with the Closing of the Genometrix IPO (as defined
below), Motorola shall purchase and Genometrix shall issue and sell to Motorola
at the Per-Share Purchase Price (as defined below) such number of shares of the
Common Stock of Genometrix (the "Purchased Common Shares") as shall equal, to
the nearest whole number, the lesser of (a) the sum of $10,000,000 divided by
the per share offering Price to Public set forth on the cover page of the final
Prospectus, as defined below (the "Per-Share Purchase Price"), and (b) that
number of shares such that the Purchased Common Shares equal fifteen percent
(15%) of the total number of shares of Common Stock issued in the Genometrix IPO
in the first closing (i.e. exclusive of the shares sold in connection with the
exercise of the Underwriters' over allotment option) (collectively, "Motorola
Stock Purchase Commitment"). The term "Prospectus" as used herein shall mean the
prospectus, as amended, on file with the SEC at the time the Registration
Statement becomes effective, including the information deemed to be part of the
Registration Statement at the time of effectiveness pursuant to Rule 430A, if
applicable, except that if the prospectus filed by Genometrix pursuant to Rule
424(b) differs from the prospectus on file at the time the Registration
Statement becomes effective, the term "Prospectus" shall refer to the Rule
424(b) Prospectus from and after the time it was filed with the SEC or
transmitted to the SEC for filing. The "Closing" as used herein shall mean the
first date upon which Genometrix receives from the Underwriters the proceeds of
the Genometrix IPO, less underwriting discount and commissions.

         Genometrix represents to Motorola that:

         1.       As of the date of the underwriting agreement entered into with
                  the Underwriters of the Genometrix IPO (the "Underwriting
                  Agreement"), the representations and warranties set forth in
                  such Underwriting Agreement will be true and correct in all
                  respects and incorporated by reference herein.

         2.       Genometrix is a corporation duly organized, validly existing
                  and in good standing under the laws of the State of Delaware.
                  Genometrix has full power and authority to own and operate its
                  properties and assets, and to carry on its business as
                  presently conducted. Genometrix is duly qualified, is
                  authorized to do business and is in good standing as a foreign
                  corporation in all jurisdictions in which the nature of its
                  activities and of its properties (both owned and leased) makes
                  such qualification necessary, except for those jurisdictions,
                  in the aggregate, in which failure to do so would not have a
                  material adverse effect on Genometrix or its business.

         3.       All corporate action on the part of Genometrix, its officers,
                  directors and shareholders necessary for the authorization,
                  execution and delivery of this Agreement, for the sale and
                  issuance of the Purchased Common Shares pursuant hereto and
                  for the performance of Genometrix's obligations hereunder has
                  been taken or will be taken prior to the Closing. This
                  Agreement, when executed and delivered, will be a valid and
                  binding obligation of Genometrix enforceable in accordance
                  with its terms. The sale of the Purchased Common Shares is not
                  and will not be subject to any preemptive rights or rights of
                  first refusal that have not been properly waived or complied
                  with.


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         4.       The execution, delivery and performance of and compliance with
                  this Agreement and the issuance and sale of the Purchased
                  Common Shares pursuant hereto will not (i) materially conflict
                  with, or result in a material breach or violation of, or
                  constitute a material default under, or result in the creation
                  or imposition of any material lien, (ii) violate, conflict
                  with or result in the breach of any material terms of, or
                  result in the material modification of, any material contract
                  or otherwise give any other contracting party the right to
                  terminate a material contract, or constitute (or with notice
                  or lapse of time both constitute) a material default under any
                  material contract to which Genometrix is a party or by or to
                  which it or any of its assets or properties may be bound or
                  subject or (iii) result in any violation, or be in conflict
                  with or constitute a default under any term, of its Articles
                  of Incorporation or bylaws.

         5.       The Purchased Common Shares which will be purchased by
                  Motorola hereunder, when issued, sold and delivered in
                  accordance with the terms hereof for the consideration
                  expressed herein, will be duly and validly authorized and
                  issued, fully paid and nonassessable, and will be free of any
                  liens or encumbrances.

         6.       There is no action, suit, proceeding nor, to Genometrix'
                  knowledge, any investigation pending or currently threatened
                  against Genometrix, that questions the validity of this
                  Agreement or the right of Genometrix to enter into such
                  agreements, or which might result, either individually or in
                  the aggregate, in any material adverse change in the assets,
                  condition, affairs or prospects of Genometrix, financial or
                  otherwise.

         7.       No consent, approval or authorization of, or designation,
                  declaration or filing with, any governmental authority on the
                  part of Genometrix is required in connection with the valid
                  execution, delivery, and performance of this Agreement or the
                  offer, sale or issuance of the Purchased Common Shares, or the
                  consummation of any other transaction contemplated by this
                  Agreement except certain filings as may be required under the
                  Securities Act and state securities laws and regulations,
                  which filings will be made timely in accordance with the
                  applicable law or regulation.


         The Motorola Stock Purchase Commitment is conditioned on the following:

         1.       As of the Closing, there shall be no material adverse change
                  in the financial condition or operations of Genometrix since
                  December 31, 1999, such determination to be made, in part, on
                  any changes set forth in the final Prospectus;

         2.       The Closing shall occur concurrently with the closing of the
                  Motorola Stock Purchase Commitment;

         3.       The representations made by Genometrix set forth above shall
                  be true and correct as of the Closing and Motorola shall have
                  received a Certificate of the Chief Executive Officer and
                  Corporate Secretary of Genometrix to that effect;


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         4.       Genometrix shall have caused to be delivered an opinion of
                  counsel to Motorola in form and substance customary for a
                  transaction of this nature, and Motorola shall have received
                  such further documents and assurances as are customary and
                  prudent in a transaction of this nature;

         5.       Notwithstanding anything else in this Agreement, if the sale
                  and issuance of the Purchased Common Shares is subject to the
                  premerger notification requirements of the Hart-Scott-Rodino
                  Antitrust Improvements Act of 1976, as amended (the "HSR
                  Act"), it shall be a condition to the Motorola Stock Purchase
                  Commitment that any waiting period under the HSR Act
                  applicable to the purchase of the Purchased Common Shares
                  shall have expired or been terminated and any approvals
                  required thereunder shall have been obtained, and the parties
                  shall cooperate in promptly filing premerger reports and in
                  taking all steps reasonably necessary to obtain early
                  termination of any applicable HSR Act waiting periods. If any
                  such waiting period shall not have expired or been subject to
                  early termination on or before the date ninety (90) days from
                  the date of this Agreement, either party may terminate this
                  Agreement by giving written notice to the other.

         6.       If the Closing does not occur by September 30, 2000, Motorola
                  in its discretion may elect to terminate this Agreement by
                  providing written notice to Genometrix at any time thereafter.

         Effective upon the purchase by Motorola of the Purchased Common Shares,
(i) the Registration Rights Agreement shall be, without further action by
Motorola or Genometrix, be deemed to be amended such that the term "Registrable
Securities", as defined therein, shall further include the Purchased Common
Shares, and Motorola shall be entitled to all the rights with respect to the
registration of the Purchased Common Shares with the SEC as are set forth in the
Registration Rights Agreement; and (ii) the Lock-Up Letter Agreement from
Motorola to the Underwriters, dated March 15, 2000, would, by the terms set
forth herein, include the Purchased Common Shares.

         Motorola represents to Genometrix that:

         1.       Motorola is an "accredited investor" as such term is defined
                  in Rule 501 of Regulation D under the Securities Act and is a
                  sophisticated investor and has such knowledge and experience
                  in financial, tax, business matters, securities and
                  investments including, without limitation, experience in
                  investments such as the purchase of the Purchased Common
                  Shares, as to enable Motorola to utilize the information made
                  available to it in connection with the sale of the Purchased
                  Common Shares, to evaluate the merits and risks of an
                  investment in the Purchased Common Shares and to make an
                  informed investment decision with respect thereto;

         2.       Motorola understands that the issuance and sale of the
                  Purchased Common Shares have not been, and except as provided
                  in the Registration Rights Agreement, will not be, registered
                  under the Securities Act of 1933, as amended (the "Securities
                  Act") or


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                  any state securities laws;

         3.       Motorola is acquiring the Purchased Common Shares solely for
                  its own account for investment and not with a view to resale
                  or distribution and has no present intention of transferring
                  the Purchased Common Shares to any other person or entity,
                  except, at Motorola's election, to a majority-owned subsidiary
                  of Motorola;

         4.       Motorola understands that it must bear the economic risk of
                  the investment indefinitely because none of the Purchased
                  Common Shares have been registered under applicable securities
                  laws and therefore, none of the Purchased Common Shares may be
                  sold, hypothecated or otherwise disposed of unless
                  subsequently registered under the Securities Act and
                  applicable state securities laws or an exemption from
                  registration is available and, accordingly, that a legend
                  shall be placed on the certificate(s) representing the
                  Purchased Common Shares in substantially the following form;

                  "THE SHARES REPRESENTED BY THIS CERTIFICATE HAVE BEEN TAKEN
                  FOR INVESTMENT AND THEY MAY NOT BE SOLD OR OTHERWISE
                  TRANSFERRED BY ANY PERSON, INCLUDING A PLEDGEE, UNLESS (1)
                  EITHER (A) A REGISTRATION STATEMENT WITH RESPECT TO SUCH
                  SHARES SHALL BE EFFECTIVE UNDER THE SECURITIES ACT OF 1933, AS
                  AMENDED, OR (B) GENOMETRIX SHALL HAVE RECEIVED AN OPINION OF
                  COUNSEL SATISFACTORY TO IT THAT AN EXEMPTION FROM REGISTRATION
                  UNDER SUCH ACT IS THEN AVAILABLE, AND (2) THERE SHALL HAVE
                  BEEN COMPLIANCE WITH ALL APPLICABLE STATE SECURITIES LAWS."

         5.       The representations of Motorola contained herein are accurate
                  and may be relied upon by Genometrix in determining the
                  availability of an exemption from registration under the
                  Securities Act and state securities laws in connection with
                  the offering and sale of the Purchased Common Shares;

         6.       Motorola has full right, power, authority and capacity to
                  enter into this Agreement and to consummate the transactions
                  contemplated hereby, and thereby and has taken all necessary
                  corporate action to authorize the execution, delivery and
                  performance of this Agreement, and this Agreement will
                  constitute the valid and binding obligations of Motorola
                  enforceable against Motorola.

         This Agreement shall be governed in all respects by the laws of the
State of Delaware. The representations, warranties, covenants and agreements
made herein shall survive any investigation made by Motorola and the closing of
the transactions contemplated hereby. This Agreement may be amended or modified
only upon the written consent of the parties hereto. This Agreement may be
executed in any number of counterparts, each of which shall be deemed an
original, but all of which together shall constitute one instrument.


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         Genometrix agrees that the material terms of this Agreement will be no
less favorable to Motorola than the terms given to other investors (including
investors that may enter into such agreements after the date hereof, if any)
that are purchasing shares of Genometrix capital stock in private placements
that are closing concurrently with the Closing.

         If the foregoing is in conformity with your understanding and agreed
to, please sign below where indicated.

                           GENOMETRIX INCORPORATED



                           By:  /s/ Mitchell D. Eggers
                                ----------------------
                                Mitchell D. Eggers
                           Its: Chief Executive Officer


         The foregoing is in conformity with our understanding and agreed to as
of this twenty-seventh day of March, 2000.

                           MOTOROLA, INC.


                           By:  /s/ Keith Bane
                                --------------
                                Keith Bane

                           Its: Executive Vice President and President of Global
                                Strategy and Corporate Development


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