<PAGE>   1
                                                                    EXHIBIT 4.20


                          SECURITIES PURCHASE AGREEMENT

         SECURITIES PURCHASE AGREEMENT (this "Agreement"), dated as of
          , 2000 between PerkinElmer, Inc., a Massachusetts corporation (the
"Purchaser"), and the undersigned equity holder (the "Holder") of Genomic
Solutions Inc., a Delaware corporation (the "Company").

                                    RECITALS

         WHEREAS, the Purchaser and the Company have entered into an Investment
Agreement dated as of December 14, 1999 (the "Investment Agreement"), a copy of
which the Company has delivered to the Holder, providing for the purchase by the
Purchaser of capital stock in the Company;

         WHEREAS, the Purchaser and the Company have entered into a Sales,
Marketing and Distribution Agreement, dated as of December 14, 1999 (the
"Distribution Agreement"), providing for the distribution by the Purchaser of
products of the Company;

         WHEREAS, the Purchaser and the Company wish to provide the Purchaser
with the option to acquire all of the outstanding equity securities of the
Company, and the Board of Directors of the Company has recommended that each
holder of the Company's equity securities execute an agreement in the form of
this Agreement (collectively, the "Securities Purchase Agreements");

         WHEREAS, a condition to the consummation of the transactions
contemplated by the Investment Agreement is the execution of Securities Purchase
Agreements by holders of capital stock, options or warrants of the Company who
hold in the aggregate no less than 85% of the outstanding shares of the
Company's common stock, $.001 par value per share (the "Common Stock"), assuming
the full conversion into, exercise for and exchange for Common Stock of all of
the Company's securities convertible into, exercisable for or exchangeable for
Common Stock; and

         WHEREAS, the Holder desires to grant to the Purchaser an irrevocable
option to purchase all of the equity securities of the Company, including
capital stock, convertible securities, options and warrants (collectively, the
"Equity Securities") owned by the Holder (such Equity Securities owned by the
Holder are hereinafter referred to as "Holder Securities") in order to induce
the Purchaser to consummate the transactions contemplated by the Investment
Agreement.


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<PAGE>   2


         NOW, THEREFORE, in consideration of these premises and good and
valuable consideration, the receipt and sufficiency of which is hereby
acknowledged, the parties hereto agree as follows:

         1. Grant of Option. Upon the terms and subject to the conditions herein
set forth, the Holder hereby grants the Purchaser an irrevocable option (the
"Option") to purchase all of the Holder Securities, free and clear of all liens,
claims, pledges, charges, restrictions, equities, options, voting rights and
encumbrances of any nature whatsoever (collectively, "Encumbrances"). The Option
may be exercised only if the Purchaser concurrently gives an exercise notice
pursuant to Section 2 of each of the Securities Purchase Agreements executed by
other holders of Equity Securities.

         2. Exercise of Option.

            (a) Subject to Section 2(b), the Option may be exercised at any time
and from time to time subsequent to the Effective Date until the Termination
Date (each as defined in Section 5), by written notice delivered to the Holder
as provided in Section 14 (the "Exercise Notice"). The closing of a purchase
specified in any Exercise Notice shall take place five business days after the
later of (i) the date the Exercise Notice is given or (ii) the expiration or
termination of all applicable waiting periods under the Hart-Scott-Rodino
Antitrust Improvements Act of 1976, as amended (the "HSR Act"). At the closing,
the Purchaser shall send to the Holder by a reputable nationwide overnight
courier service a check in the amount of the consideration payable for the
Holder Securities being purchased from the Holder, and the Purchaser shall take
all such actions necessary to effect the assignment to the Purchaser of the
Holder Securities being purchased and the vesting in the Purchaser of good and
marketable title thereto. The Purchaser shall thereafter be treated for all
purposes as the owner of such Holder Securities. Without limiting the foregoing,
the Purchaser is hereby authorized (x) to deliver Transfer Instruments (as
defined in Section 5) to the Company or its transfer agent to effect the
assignment of such Holder Securities to the Purchaser and (y) to require the
Company or its transfer agent to register the Purchaser as the record owner of
such Holder Securities.

            (b) The Purchaser may exercise the Option at any time on the
Effective Date by delivering an Exercise Notice to the Company on the Effective
Date and subsequently promptly delivering an Exercise Notice to the Holder in
accordance with Section 14. If the Purchaser does not exercise the Option as
provided in the immediately preceding sentence, the Company shall be deemed to
have given notice to the Purchaser (an "IPO Notice") on the day after the
Effective Date that it intends to file a registration statement with the
Securities and Exchange Commission relating to an initial public offering of
Common Stock (or callable common stock) (the "Registration Statement") firmly
underwritten by a nationally recognized underwriter who certifies to the
Purchaser that such underwriter believes that (i) the offering will result in no
less than $20,000,000 of gross proceeds to the Company and (ii) the securities
offered will qualify for listing on the New York Stock Exchange or the National
Market Tier of the Nasdaq Stock Market (an initial public offering that in fact
results in no less than $20,000,000 of gross proceeds to the Company and the
listing of the offered securities on the New York Stock Exchange or the National
Market Tier of the Nasdaq Stock Market is hereinafter referred to as a
"Qualified IPO"). Following the filing of an IPO Notice, the


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Purchaser shall not have the right to exercise the Option until the expiration
of the 180-day period following consummation of the initial public offering;
provided, however, that the Purchaser shall have the right to exercise the
Option at any time after (x) withdrawal or abandonment of the Registration
Statement by the Company or (y) consummation of an initial public offering that
is not a Qualified IPO. The Company may at any time notify the Purchaser that it
is revoking an IPO Notice, in which event the Purchaser shall have the right to
exercise the Option at any time after the notice of revocation is given. If the
Company revokes an IPO Notice, it may subsequently give one or more additional
IPO Notices, in each instance upon no less than 30 days' prior notice to the
Purchaser. In no event shall the Purchaser be prohibited from exercising the
Option for an aggregate number of days exceeding 270 days.

         3. Purchase Price.

            (a) Upon the closing of a purchase of Holder Securities following
the exercise of the Option, the Purchaser shall pay the Holder the purchase
price set forth in this Section 3. The purchase price shall be calculated based
on the number of days that have elapsed between the Effective Date and the date
on which the Exercise Notice is given, as set forth in the table below. The
purchase price (the "Option Price") for Holder Securities that are Common Stock
(subject to adjustment for stock splits, recapitalization, reclassifications or
similar events) shall be as set forth below:
<TABLE>
<CAPTION>

        ------------------------------- ----------------------------------------
                                                Number of Days that have
             Price Per Share of              Elapsed between the Effective
             Common Stock                    Date and the Date the Exercise
                                                    Notice is Given
<S>                                     <C>
        ------------------------------- ----------------------------------------
                    $6.75                             1 through 182
        ------------------------------- ----------------------------------------
                    $7.00                            183 through 365
        ------------------------------- ----------------------------------------
                    $7.50                            366 through 548
        ------------------------------- ----------------------------------------
                    $8.00                            549 through 730
        ------------------------------- ----------------------------------------
</TABLE>

; provided, however, that no days during which the Purchaser is prohibited from
exercising the Option pursuant to Section 2(b) shall be included in calculating
the number of days that have elapsed between the Effective Date and the date of
giving of the Exercise Notice.

            (b) The purchase price payable for any Holder Securities that are
not Common Stock shall be calculated on the basis of the number of shares of
Common Stock into or for which the Holder Security is convertible, exercisable
or exchangeable, net of any conversion, exercise or exchange price that would be
payable by the Holder upon such conversion, exercise or exchange.
Notwithstanding the foregoing, in lieu of paying cash for Holder Securities that
are employee stock options, the Purchaser may assume such stock options and
substitute therefor the option to acquire, on the same terms and conditions,
such number of shares of common stock of the Purchaser as is equal to the number
of shares of Common Stock subject to the unexercised portion of such option
multiplied by the Conversion Ratio (as defined below), with any fraction
resulting from such multiplication to be rounded down to the nearest whole
number. The exercise price per share of each such assumed option shall be equal
to the exercise price of such


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option immediately prior to the giving of the Exercise Notice divided by the
Conversion Ratio, rounded up to the nearest whole cent. The term,
exercisability, vesting schedule and all of the other terms of the stock option
shall remain unchanged. "Conversion Ratio" shall mean the purchase price per
share of Common Stock calculated pursuant to Section 3(a), divided by the
average of the last reported sale prices per share, over the 30 trading days
ending on the trading day prior to the day the Exercise Notice is given, of the
Purchaser's common stock, as reported on the New York Stock Exchange.

            (c) The Option Prices set forth in Section 3(a) shall be subject to
adjustment from time to time as follows:

               (i) If the Company shall at any time or from time to time issue
            any shares of Common Stock, or securities convertible into or
            exercisable for Common Stock (including any shares of Common Stock
            deemed to have been issued pursuant to subdivision (iv)(c) below)
            other than Excluded Stock (as defined in clause (v) below) without
            consideration or for a consideration per share less than the Option
            Price in effect immediately prior to the issuance of such Common
            Stock, then any Option Price that is greater than the consideration
            per share of Common Stock or its equivalent received in such
            issuance or sale shall forthwith be lowered to be equal to the
            quotient obtained by dividing:

                   (a) an amount equal to the sum of (x) the total number of
               shares of Common Stock outstanding (including any shares of
               Common Stock deemed to have been issued pursuant to subdivision
               (iv)(c) below and any additional shares that would be issued as a
               result of giving effect to any anti-dilution provisions that are
               triggered by the issuance in question) immediately prior to such
               issuance, multiplied by the applicable Option Price in effect
               immediately prior to such issuance, and (y) the consideration
               received by the corporation upon such issuance (other than any
               consideration received from the Purchaser); by

                   (b) the total number of shares of Common Stock outstanding
               (including any shares of Common Stock deemed to have been issued
               pursuant to subdivision (iv)(c) below and any additional shares
               that would be issued as a result of giving effect to any
               anti-dilution provisions that are triggered by the issuance in
               question) immediately after the issuance of such Common Stock
               (excluding any shares of such Common Stock purchased by the
               Purchaser).

            For the purposes of any adjustment of any Option Price pursuant to
            this clause, the following provisions shall be applicable:

               (ii) In the case of the issuance of Common Stock for cash,
            the consideration shall be deemed to be the amount of cash paid
            therefor after deducting therefrom any discounts, commissions or
            other expenses allowed, paid or incurred by the corporation for
            any underwriting or otherwise in connection


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<PAGE>   5

            with the issuance and sale thereof.

                           (iii) In the case of the issuance of Common Stock for
            a consideration in whole or in part other than cash, the
            consideration other than cash shall be deemed to be the fair market
            value thereof as determined in good faith by the Company's Board of
            Directors, irrespective of any accounting treatment.

                           (iv) In the case of the issuance of options to
            purchase or rights to subscribe for Common Stock, securities by
            their terms convertible into or exchangeable for Common Stock, or
            options to purchase or rights to subscribe for such convertible or
            exchangeable securities:

                                    (a) the aggregate maximum number of shares
                           of Common Stock deliverable upon exercise of such
                           options to purchase or rights to subscribe for Common
                           Stock shall be deemed to have been issued at the time
                           such options or rights were issued and for a
                           consideration equal to the consideration (determined
                           in the manner provided in subdivisions (ii) and (iii)
                           above), if any, received by the Company upon the
                           issuance of such options or rights plus the minimum
                           purchase price provided in such options or rights for
                           the Common Stock covered thereby;

                                    (b) the aggregate maximum number of shares
                           of Common Stock deliverable upon conversion of or in
                           exchange for any such convertible or exchangeable
                           securities or upon the exercise of options to
                           purchase or rights to subscribe for such convertible
                           or exchangeable securities and subsequent conversion
                           or exchange thereof shall be deemed to have been
                           issued at the time such securities, options, or
                           rights were issued and for a consideration equal to
                           the consideration received by the Company for any
                           such securities and related options or rights
                           (excluding any cash received on account of accrued
                           interest or accrued dividends), plus the additional
                           consideration, if any, to be received by the Company
                           upon the conversion or exchange of such securities or
                           the exercise of any related options or rights (the
                           consideration in each case to be determined in the
                           manner provided in subdivisions (ii) and (iii)
                           above);

                                    (c) on any change in the number of shares or
                           exercise price of Common Stock deliverable upon
                           exercise of any such options or rights or conversions
                           of or exchange for such securities, including without
                           limitation a change resulting from the antidilution
                           provisions thereof, each Option Price previously
                           adjusted shall forthwith be readjusted to such Option
                           Price as would have been obtained had the adjustment
                           made upon the issuance of such options, rights or
                           securities not converted prior to such change or
                           options or rights related to such securities not
                           converted prior to such change been made upon the
                           basis of such change; and

                                    (d) on the expiration of any such options or
                           rights, the



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                          termination of any such rights to convert or exchange
                          or the expiration of any options or rights related to
                          such convertible or exchangeable securities, each
                          Option Price previously adjusted shall forthwith be
                          readjusted to such Option Price as would have obtained
                          had the adjustment made upon the issuance of such
                          options, rights, securities or options or rights
                          related to such securities been made upon the basis of
                          the issuance of only the number of shares of Common
                          Stock actually issued upon the exercise of such
                          options or rights, upon the conversion or exchange of
                          such securities, or upon the exercise of the options
                          or rights related to such securities and subsequent
                          conversion or exchange thereof.

                          (v) "Excluded Stock" means (1) shares of Common Stock
                  issued by the Company as a stock dividend or upon any
                  subdivision, split-up or combination of shares of Common
                  Stock; (2) shares of Common Stock issued upon exercise of
                  incentive or non-qualified stock options outstanding as of the
                  date hereof; (3) shares of Common Stock issued upon exercise
                  of incentive or non-qualified options granted after the date
                  hereof in the ordinary course of business consistent with past
                  practice to employees, consultants or non-employee directors
                  pursuant to the existing stock option plans adopted by the
                  Board of Directors; (4) shares of Common Stock issued by the
                  Company upon conversion of shares of Preferred Stock; (5)
                  shares of Common Stock issued upon exercise of any warrants
                  issued to ESA, Inc., a Massachusetts corporation, pursuant to
                  the Warrant to Purchase Common Stock of Genomic Solutions Inc.
                  dated October 13 1998, (6) shares of Common Stock issued upon
                  exercise of any warrants issued pursuant to the terms of the
                  Business Loan Agreement between the Company, White Pines
                  Limited Partnership I and others dated April 23, 1999 (the
                  "April Loan Agreement"); (7) shares of Common Stock issued
                  upon exercise of any warrants issued pursuant to the terms of
                  the Business Loan Agreement between the Company, White Pines
                  Limited Partnership I and others dated October 28, 1999 (the
                  "October Loan Agreement", and, together with the April Loan
                  Agreement, the "Loan Agreements"); or (8) shares of Common
                  Stock issued to the Lenders (as defined in the Loan
                  Agreements) in partial payment of interest on the promissory
                  notes delivered to the Lenders under the Loan Agreements.

                          (vi) All adjustments to the Option Prices made
                  pursuant to this Section 3(c) shall be rounded to the nearest
                  cent.

         4. Delivery of Transfer Instruments. The Holder has delivered to the
Purchaser, or will deliver on or prior to the Effective Date, original stock
certificates, option agreements, warrants and other instruments evidencing the
ownership of the Holder Securities, with stock powers, in the case of capital
stock, and instruments of assignment, in the case of options and warrants,
attached and duly executed in blank (collectively, the "Transfer Instruments").
The Purchaser shall hold the Transfer Instruments pursuant to the terms of this
Agreement and use them only for the purposes set forth in this Agreement.

         5.       Termination.


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                  (a) The "Effective Date" shall mean the Closing Date, as
defined in the Investment Agreement. The obligations of the Purchaser and the
Holder under this Agreement will terminate at 5:00 p.m., Boston time, on the
second anniversary of the Effective Date (the "Termination Date"); provided,
however, that the Termination Date shall be extended by the aggregate number of
days during which the Purchaser is prohibited from exercising the Option
pursuant to Section 2(b) hereof; provided, further, that if the Purchaser gives
the Exercise Notice prior to the Termination Date, this Agreement shall continue
in effect until the consummation of the purchase set forth in the Exercise
Notice. Promptly following the Termination Date, the Purchaser shall deliver to
the Holder all Transfer Instruments relating to Holder Securities for which no
Exercise Notice was given prior to the Termination Date.

                  (b) Notwithstanding the foregoing, if (i) the Company has
given the Purchaser an IPO Notice that has not been revoked, (ii) the Company
notifies the Purchaser that it has resolved all comments made by the staff of
the Securities and Exchange Commission relating to the proposed initial public
offering and is prepared to seek effectiveness of the Registration Statement and
(iii) simultaneously with or after the notice described in clause (ii) above,
the lead underwriter for the proposed initial public offering certifies to the
Purchaser that the offering will be a Qualified IPO, then the Termination Date
shall occur on the effective date of the reclassification of the equity
securities contemplated by Section 7.7(c) of the Investment Agreement pursuant
to which the Equity Securities are exchanged for similar securities of the
Company that are callable by the Company. Promptly following the Termination
Date described in this section 5(b), the Purchaser shall deliver all of the
Transfer Instruments it then holds to the Company.

                  (c) Promptly following the Termination Date, the Purchaser
shall file termination statements on Form UCC-3 with respect to all Holder
Securities for which no Exercise Notice has been given.

         6. Holder's Representations and Warranties. The Holder represents and
warrants to the Purchaser that as of the Effective Date:

                  (a) the Holder is the owner of, and has good and marketable
title to, the Holder Securities and the Holder Securities represent all the
capital stock of the Company, or securities convertible into, exercisable for or
exchangeable for capital stock of the Company, owned by the Holder, directly or
indirectly;

                  (b) except as set forth in the Stockholders Agreement, dated
as of December 24, 1997, among the Company and certain of its shareholders, as
amended, the Holder owns the Holder Securities free and clear of all
Encumbrances, except for the security interest granted herein;

                  (c) the Holder has the full and unrestricted legal power,
authority and right to enter into, execute, deliver and perform this Agreement;

                  (d) the Holder has the full and unrestricted legal power,
authority and right to sell, transfer and convey the Holder Securities to the
Purchaser as provided in this Agreement;


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<PAGE>   8

            (e) the Holder has duly executed and delivered this Agreement
and this Agreement constitutes a valid and binding agreement of the Holder
enforceable in accordance with its terms; and

            (f) neither the execution nor the delivery of this Agreement
by the Holder nor the consummation by the Holder of the transactions
contemplated hereby will (A) to the knowledge of the Holder, require the
consent, waiver, approval, license or authorization of, or any filings with any
person or public authority, other than any filings by the Purchaser under the
HSR Act, (B) with or without the giving of notice or lapse of time or both,
conflict with or constitute a violation of, or default on, or give rise to any
right of acceleration under any indenture, contract, commitment, agreement,
arrangement or other instrument of any kind to which the Holder is a party or by
which the Holder is bound, or (C) to the knowledge of the Holder, violate any
existing applicable law, rule, regulation, judgment, order or decree of any
governmental instrumentality or court having jurisdiction over the Holder.

         7. Holder's Covenants. The Holder covenants and agrees with the
Purchaser that:

            (a) any Equity Securities obtained by the Holder after the date
hereof, including without limitation any shares into or for which Equity
Securities are converted or exercised, shall be deemed to be "Holder Securities"
and thereby subject to this Agreement; provided, however, that the Purchaser
shall not be required to make any payment pursuant to Section 3 hereof to
acquire any employee stock options that are granted after the Effective Date to
the extent such options are not vested on the date the Exercise Notice is given;
and

            (b) Holder shall not permit any Encumbrances to attach to the Holder
Securities.

         8. Grant of Security Interest. In order to secure the Holder's
obligations hereunder, effective as of the Effective Date, the Holder hereby
pledges and grants to the Purchaser a security interest in all of the Holder
Securities. The Holder shall retain the rights to vote, to transfer (as provided
in Section 12 hereof), to receive dividends on and to exercise or convert any
Holder Security until an Exercise Notice for such Holder Security has been given
hereunder.

         9. Waiver of Rights of First Refusal, etc. Holder hereby waives all
rights to consent, rights of first refusal, rights of first offer, pre-emptive
rights, tag along rights, drag along rights and other rights to acquire Equity
Securities of the Company as such rights in any way relate to (i) the purchase
by the Purchaser of capital stock of the Company pursuant to the Investment
Agreement, (ii) the exercise by the Purchaser of its rights under any of the
other Securities Purchase Agreements or (iii) the exercise of Call Rights (as
defined in the Investment Agreement) by the Company at the direction of the
Purchaser.

         10. Direction to Deliver Shares. The Holder hereby irrevocably directs
the Company, upon the conversion, exercise or exchange of any Equity Securities
into or for Common Stock, to deliver such shares of Common Stock to the
Purchaser to be held in accordance with the terms of this Agreement. The Company
hereby consents to such direction and agrees to deliver any such shares of
Common Stock to the Purchaser upon delivery by the Purchaser of Holder
Securities



                                      -8-

<PAGE>   9

for conversion.

         11. Attorney-in-Fact. The Holder hereby irrevocably constitutes the
Purchaser, and empowers the Purchaser to act, as its attorney-in-fact with
authority to execute, acknowledge and swear to all instruments and file all
documents, including without limitation financing statements on Form UCC-1,
requisite to carrying out the intention and purpose of this Agreement. The power
of attorney granted hereby shall be irrevocable and shall be deemed to be a
power coupled with an interest and shall survive the bankruptcy, death,
incompetence or dissolution of the Holder.

         12. Restrictions on Transfer. The Holder shall not transfer any of the
Holder Securities except to a transferee who executes a counterpart of this
Agreement.

         13. Specific Performance. The Holder acknowledges that damages would be
an inadequate remedy for any breach of the provisions of this Agreement and
agrees that the obligations of the Holder hereunder shall be specifically
enforceable and the Holder shall not take any action to impede the Purchase from
seeking to enforce such right of specific performance.

         14. Notices. All notices, requests, claims, demands and other
communication hereunder shall be in writing and shall be deemed fully delivered
on the date of personal delivery or one business day after it is sent via a
reputable nationwide overnight courier service, or three business days after it
is sent by U.S. registered or certified mail, return receipt requested, postage
prepaid, in each case to the Holder at the address set forth below the Holder's
name on the signature page hereof, and to the Purchaser at: 45 William Street,
Wellesley, MA 02481, attention: Terrance L. Carlson, Esq. and a copy to Hale and
Dorr LLP, 60 State Street, Boston, MA 02109, attention: David E. Redlick, Esq.
and Kenneth A. Hoxsie, Esq., or to such other address as either party may
furnish to the other in writing in accordance herewith.

         15. Successors and Assigns. This Agreement shall inure to the benefit
of and be binding upon the parties hereto and their respective heirs, personal
representatives, successors and assigns.

         16. Assignment of Purchaser. The Purchaser may, without the consent of
the Holder, assign its rights under this Agreement to one or more of its
affiliates, so long as the Purchaser remains primarily liable for its
obligations hereunder.

         17. Governing Laws. This Agreement and the transactions contemplated
herein shall be governed by, and this Agreement shall be construed in accordance
with, the laws (and not the law of conflicts) of the State of Delaware as to all
issues or matters. Each of the parties hereto (a) submits to the jurisdiction of
any state or federal court sitting in Delaware in any action or proceeding
arising out of or relating to this Agreement, (b) agrees that all claims in
respect of the action or proceeding may be heard and determined in any such
court, (c) agrees not to bring any action or proceeding arising out of or
relating to this Agreement in any other court and (d) waives any right it may
have to a trial by jury with respect to any action or proceeding arising out of
or relating to this Agreement. Each of the parties waives any defense of
inconvenient forum to the



                                      -9-
<PAGE>   10

maintenance of any action or proceeding so brought and waives any bond,
surety or other security that might be required of any other party with respect
thereto. Any party hereto may make service on another party hereto by sending or
delivering a copy of the process to the party to be served at the address and in
the manner provided for giving of notices in Section 14. Nothing in this Section
17, however, shall affect the right of any party hereto to serve legal process
in any other manner permitted by law.

         18. Execution in Counterpart. This Agreement may be executed in several
counterparts, each of which shall be an original, but all of which together
shall constitute one and the same agreement.

         19. Severability. The invalidity or unenforceability of any provision
of this Agreement shall not affect the validity or enforceability of any other
provision of this Agreement, which shall remain in full force and effect.

20. Amendment and Waiver. No amendment or waiver of any provision of this
Agreement or consent to departure therefrom shall be effective unless in writing
and signed by the Purchaser and the Holder, in the case of an amendment, or by
the party which is the beneficiary of such provision, in the case of a waiver or
consent to departure therefrom.

         21. Entire Agreement. This Agreement sets forth the entire
understanding of the parties hereto and supersedes all prior agreements,
covenants, arrangements, communications, representations and warranties, whether
oral or written, by either party.

         22. Further Assurances. From time to time, at the Purchaser's request
and without further consideration, the Holder will execute and deliver to the
Purchaser such documents and take such action as the Purchaser may reasonably
request in order to consummate more effectively the transactions contemplated
hereby and to vest in the Purchaser good, valid and marketable title to the
Holder Securities that are purchased by the Purchaser in accordance with the
terms hereof, including, but not limited to, using its best efforts to cause the
Company or its transfer agent to transfer the Holder Securities on the transfer
books of the Company to the Purchaser.

         IN WITNESS WHEREOF, this Agreement has been duly executed by the
parties hereto as of the day and year first above written.

                                   PURCHASER:

                                   PerkinElmer, Inc.

                                   By
                                      ----------------------------------------
                                      Name:
                                      Title:


                                   HOLDER:


                                      -10-
<PAGE>   11


                                        ----------------------------------------

                                        By
                                          --------------------------------------

                                        Address:
                                                --------------------------------
                                        ----------------------------------------


                                      -11-
<PAGE>   12


         Genomic Solutions Inc., hereby
         consents to and agrees to be bound
         by the provisions of Section 10 of
         this Agreement

         By:
            -------------------------------



                                      -12-