<PAGE>

                                                                     EXHIBIT 4.3


                            STOCK PURCHASE AGREEMENT


     THIS STOCK PURCHASE AGREEMENT (the "Agreement") is made as of
______________, by and among Applied Imaging Corp., a Delaware corporation (the
"Company"), and the investors listed on Schedule I hereto ("Investors").
                                        ----------

     1.   Purchase and Sale of Stock.  Subject to the terms and conditions of
          --------------------------
this Agreement, Investors agree to purchase at the Initial Closing (as
hereinafter defined), and the Company agrees to sell and issue to each of the
Investors at the Initial Closing, that number of whole shares of the Company's
Common Stock as is determined by dividing the investment amount set forth
opposite each Investor's name on Schedule I hereto (collectively, the "Shares")
                                 ----------
by a purchase price per share (the "Purchase Price") equal to $_____.  In
consideration thereof, the Company shall also issue warrants to the Investors in
substantially the form of Exhibit A hereto (the "Warrants" and, together with
                          ---------
the Shares, the "Securities") for the purchase of 33 shares of Common Stock (the
"Warrant Shares") for every 100 Shares issued to such Investors hereunder.

          1.1  Initial Closing.  The initial closing of the purchase and sale of
               ---------------
Shares (the "Initial Closing") shall be held at the offices of Georgopoulos
Pahlavan & Prince, LLP, 935 Hamilton Avenue, Menlo Park, California ("GP&P"), on
___________ at 9:00 a.m., or at such other time and place upon which the Company
and Investors shall agree.

          1.2  Subsequent Closings.  The Company and the Investors agree that at
               -------------------
one or more subsequent closings (collectively, the "Subsequent Closings" and,
individually, a "Subsequent Closing"; the Initial Closing and each Subsequent
Closing are referred to herein as a "Closing"), the Company may issue and sell
shares of Common Stock ("Additional Shares") and warrants to purchase shares of
Common Stock in connection with the purchase and sale of Shares at the Initial
Closing to one or more investors who meet with the reasonable approval of the
Board of Directors of the Company (upon execution of a counterpart to this
Agreement, such investors shall for all purposes hereunder and under the
Warrants be "Investors").  Each Subsequent Closing shall be held at the offices
of GP&P at such times and dates as shall be specified by the Company.

          1.3  Adjustments.  (a)  The Company and the Investors agree that if,
               -----------
in connection with a Subsequent Closing, the Company issues Additional Shares at
a purchase price per Additional Share that is less than the Purchase Price
hereunder, then the Purchase Price hereunder shall be decreased and the number
of Shares purchased by each Investor hereunder shall be increased so as to make
the economic terms and conditions of the purchases at each Closing the same
(without any decrease in the aggregate proceeds to the Company).

<PAGE>

          (b) The Company and the Investors agree that if, in connection with
any additional public or private offering of its common stock or any security
convertible into its common stock that closes within 270 days after the Initial
Closing, the Company issues Additional Shares at a purchase price per Additional
Share that is less than the Purchase Price hereunder or issues in connection
therewith a greater percentage of additional warrants for the purchase of common
stock or any security convertible into its common stock or issues such warrants
with a lower exercise price than the warrants issued to the Investors, then the
Purchase Price hereunder shall be decreased and the number of Shares purchased
by each Investor hereunder shall be increased and/or the number of warrants
issued to each Investor in connection herewith shall be increased and/or the
exercise price of such warrants issued to each Investor shall be decreased, as
the case may be, so as to make the economic terms and conditions of the
purchases at each offering the same (without any decrease in the aggregate
proceeds to the Company).

          1.4  Delivery. Within three days of the applicable Closing, the
               --------
Company shall deliver to the Investors a certificate representing the Shares
being purchased thereby and Warrants against payment of the purchase price
therefor by wire transfer to an escrow account held by Wells Fargo Bank
Minnesota, National Association, (the "Agent"). Wire instructions are included
in Exhibit B hereto.
   ---------

     2.   Representations and Warranties of the Company.  The Company hereby
          ---------------------------------------------
represents and warrants to Investors that, except as set forth in the Schedule
of Exceptions attached hereto as Schedule II:
                                 -----------

          2.1  Organization and Standing.  The Company is a corporation duly
               -------------------------
organized and validly existing under the laws of the State of Delaware and is in
good standing under such laws.  The Company has all requisite corporate power to
own and operate its properties and assets, and to carry on its business as
presently conducted.  The Company is qualified to do business as a foreign
corporation in the State of California.  Such qualification is not presently
required in any other jurisdiction where a failure to so qualify would have a
material adverse effect on the Company.

          2.2  Capitalization.  The authorized capital stock of the Company
               --------------
consists of 20,000,000 shares of Common Stock and 6,000,000 shares of Preferred
Stock of which 13,842,037 shares of Common Stock were issued and outstanding as
of October 31, 2000. No shares of Preferred Stock are issued and outstanding.
All such issued and outstanding shares have been duly authorized and validly
issued and are fully paid and nonassessable. The Company had options to purchase
1,927,105 shares of its Common Stock issued and outstanding as of October 31,
2000 under its 1998 Incentive Stock Option Plan, Amended and Restated 1988
Incentive Stock Option Plan and Directors Option Plan. The Company has reserved
144,395 shares of Common Stock for issuance under its Employee Stock Purchase
Plan. Except as disclosed in the Company SEC Documents (as defined below), there
are no other options, warrants, conversion privileges, or preemptive or other
rights or agreements presently outstanding to purchase

                                       2
<PAGE>

or otherwise acquire any authorized but unissued shares of the capital stock or
other securities of the Company.

          2.3 Authority. The Company has full power and authority to execute and
              ---------
deliver this Agreement, and to consummate the transactions contemplated by this
Agreement. All corporate action on the part of the Company, its officers,
directors and stockholders necessary for the execution and delivery of, and the
consummation of the transactions contemplated by this Agreement and the
performance of all obligations of the Company under this Agreement, has been
taken. This Agreement, upon execution and delivery by the Company and assuming
the due and proper execution and delivery by Investor, constitutes a legal,
valid and binding obligation of the Company, enforceable in accordance with its
terms, except as may be limited by (i) applicable bankruptcy, insolvency,
reorganization or other laws of general application relating to or affecting the
enforcement of creditors rights generally, and (ii) the effect of rules of law
governing the availability of equitable remedies.

          2.4 Valid Issuance of Common Stock. The Common Stock to be sold hereby
              ------------------------------
has been duly authorized and, when issued, delivered and paid for in the manner
set forth in this Agreement, will be duly authorized, validly issued, fully paid
and nonassessable, and will be free of restrictions on transfer other than
restrictions on transfer under this Agreement and under applicable state and
federal securities laws.  The issuance and sale by the Company of Common Stock
and Warrants pursuant to this Agreement are not subject to any preemptive or
other subscription or purchase rights of any Person.  For purposes of this
Agreement, "Person" shall mean an individual, a corporation, a partnership
(general or limited), a joint venture, an association, an organization, a trust
or any other entity.

          2.5 Governmental Consents. Other than compliance with the Securities
              ---------------------
Act of 1933, as amended (the "Act") and such filings as may be required to be
made with the National Association of Securities Dealers (the "NASD"), no
consent, approval, order or authorization of, or registration, qualification,
designation, declaration or filing with, any federal, state or local
governmental authority on the part of the Company is required in connection with
the consummation of the transactions contemplated by this Agreement.

          2.6 Conflicts. The execution and delivery of this Agreement will not
              ---------
conflict with or result in a material breach of the terms, conditions or
provisions of, or constitute a material default under, any contract, covenant or
instrument under which the Company is now obligated.

          2.7 SEC Documents; Material Contracts; Financial Statements. The
              -------------------------------------------------------
Company has filed each statement, annual, quarterly and other report,
registration statement and definitive proxy statement ("Company SEC Documents")
required to be filed (other than preliminary material) by the Company with the
SEC subsequent to November 7, 1996 (the date of effectiveness of the Company's
Registration Statement on Form S-1 for the Company's initial public offering of
its Common Stock). As of their

                                       3
<PAGE>

respective filing dates, the Company SEC Documents complied in all material
respects with the requirements of the Act or the Securities Exchange Act of 1934
(the "1934 Act"), as the case may be, and none of the Company SEC Documents
contained any untrue statement of a material fact or omitted to state a material
fact required to be stated therein or necessary to make the statements made
therein, in light of the circumstances in which they were made, not misleading,
except to the extent corrected by any subsequently filed Company SEC Document.
The financial statements of the Company included in the Company SEC Documents
(the "Financial Statements") comply as to form in all material respects with
applicable accounting requirements and with the published rules and regulations
of the SEC with respect thereto. The Financial Statements have been prepared in
accordance with generally accepted accounting principles consistently applied
and fairly present the consolidated financial position of the Company and any
subsidiaries at the dates thereof and the consolidated results of operations and
consolidated cash flows for the periods then ended (subject, in the case of
unaudited statements, to normal, recurring adjustments).

          2.8 Litigation. There is no pending or threatened lawsuit,
              ----------
administrative proceeding, arbitration, labor dispute or governmental
investigation ("Litigation") to which the Company is a party or by which any
material portion of its assets, taken as a whole, may be bound and which
Litigation, if adversely determined, would have a material adverse effect on the
Company's assets, liabilities, financial condition or operations.

          2.9 Disclosure. Neither this Agreement nor any agreement, instrument
              ----------
or other documents delivered by the Company to the Investors in connection
herewith or filed with the SEC subsequent to November 1996, when read together,
contains any untrue statement of a material fact, or, to the knowledge of the
Company, omits to state a material fact necessary to be stated, when read
together, to make the statements contained herein or therein not misleading in
light of the circumstances in which they were made.

     3.   Representations and Warranties of the Investors.  Each investor hereby
          -----------------------------------------------
represents and warrants that:

          3.1 Authorization. Such Investor has full power and authority to
              -------------
execute and deliver, and to consummate the transactions contemplated by the
applicable Closing and this Agreement. All corporate action on the part of such
Investor, its officers, directors and stockholders necessary for (i) the
execution and delivery of, and the consummation of the transactions contemplated
by, this Agreement, and (ii) as of the applicable Closing, the performance of
all obligations of such Investor under this Agreement, has been taken. This
Agreement, upon execution and delivery by such Investor and assuming the due and
proper execution and delivery by the Company, constitutes a legal, valid and
binding obligation of such Investor, enforceable in accordance with its terms,
except as may be limited by (i) applicable bankruptcy, insolvency,
reorganization or other laws of general application relating to or affecting the

                                       4
<PAGE>

enforcement of creditors rights generally, and (ii) the effect of rules of law
governing the availability of equitable remedies.

          3.2 Purchase Entirely for Own Account. This Agreement is made with
              ---------------------------------
such Investor in reliance upon such Investor's representation to the Company,
which by such Investor's execution of this Agreement, such Investor hereby
confirms, that the Securities will be acquired for investment for such
Investor's own account, not as a nominee or agent, and not with a view to the
resale or distribution of any part thereof, and that such Investor has no
present intention of selling, granting any participation in, or otherwise
distributing the same. By executing this Agreement, such Investor further
represents that Investor does not have any contract, undertaking, agreement or
arrangement with any Person to sell, transfer or grant participations to such
Person or to any third Person, with respect to any of the Securities.

          3.3 Disclosure of Information. Such Investor has received all the
              -------------------------
information it considers necessary or appropriate for deciding whether to
purchase the Common Stock.  Such Investor further represents that it has had an
opportunity to ask questions and receive answers from the Company regarding the
terms and conditions of the offering of the Common Stock and the business,
properties, prospects and financial condition of the Company.

          3.4 Investment Experience. Such Investor is an investor in securities
              ---------------------
of companies in the development stage and acknowledges that it is able to
appropriately identify the inherent risks associated with, and can bear the
economic risk of its investment, and has such knowledge and experience in
financial or business matters that it is capable of evaluating the merits and
risks of the investment in the Common Stock. Such Investor has not been
organized for the purpose of acquiring the Common Stock.

          3.5 Accredited Investor. Such Investor is an "accredited investor"
              -------------------
within the meaning of SEC Rule 501 of Regulation D, as presently in effect.

          3.6 Restricted Securities. Such Investor understands that the
              ---------------------
Securities it is purchasing are characterized as "restricted securities" under
the federal securities laws inasmuch as they are being acquired from the Company
in a transaction not involving a public offering and that under such laws and
applicable regulations such securities may be resold without registration under
the Act, only in certain limited circumstances. In this connection, Investor
represents that it is familiar with SEC Rule 144, as presently in effect, and
understands the resale limitations imposed thereby and by the Act.

          3.7 Further Limitations on Disposition. Without in any way limiting
              ----------------------------------
the representations set forth above, such Investor further agrees not to make
any disposition of all or any portion of the Securities unless and until the
transferee has agreed in writing for the benefit of the Company to be bound by
this Section 3 provided and to the extent this Section is applicable, and:

                                       5
<PAGE>

              (a) There is then in effect a Registration Statement under the Act
covering such proposed disposition and such disposition is made in accordance
with such Registration Statement; or

              (b) If reasonably requested by the Company, such Investor shall
have furnished the Company with an opinion of counsel, reasonably satisfactory
to the Company, that such disposition will not require registration of such
shares under the Act. It is agreed that the Company will not require opinions of
counsel for transactions made pursuant to Rule 144 except in unusual
circumstances.

          3.8 Legends. Each certificate or instrument representing Shares shall
              -------
bear legends in substantially the following forms:

              (i)  "THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN
     REGISTERED UNDER THE SECURITIES ACT OF 1933 (THE 'SECURITIES ACT') AND ARE
     'RESTRICTED SECURITIES' AS DEFINED IN RULE 144 PROMULGATED UNDER THE
     SECURITIES ACT. THE SECURITIES MAY NOT BE SOLD OR OFFERED FOR SALE OR
     OTHERWISE DISTRIBUTED EXCEPT (I) IN CONJUNCTION WITH AN EFFECTIVE
     REGISTRATION STATEMENT FOR THE SECURITIES UNDER THE SECURITIES ACT, OR (II)
     IN COMPLIANCE WITH RULE 144, OR (III) PURSUANT TO AN OPINION OF COUNSEL
     SATISFACTORY TO THE ISSUER OF THESE SECURITIES THAT SUCH REGISTRATION OR
     COMPLIANCE IS NOT REQUIRED AS TO SUCH SALE, OFFER OR DISTRIBUTION."

              (ii) Any other legends required by California law or other
applicable blue sky or state securities laws.

The Company need not register a transfer of any Shares, and may also instruct
its transfer agent not to register a transfer of any Shares, unless the
conditions specified in the foregoing legends are satisfied to the extent
applicable.

     4.  Registration Rights.
         -------------------

          4.1 Obligations of the Company. (a) The Company shall prepare and file
              --------------------------
with the SEC as soon as practicable, but in no event later than 30 days after
the date of the Initial Closing, a registration statement to register under the
Act, Shares and Warrant Shares acquired pursuant to this Agreement by the
Investors. In the event Shares and/or Warrant Shares are issued pursuant to
Section 1.3(b), the Company shall prepare and file with the SEC as soon as
practicable, but in no event later than 30 days after the date of issuance of
such Shares and Warrant Shares, a registration statement or an amendment to a
registration to register such Shares and Warrant Shares under the Act.

          (b)  The Company shall:

                                       6
<PAGE>

              (i)   Use commercially reasonable efforts to cause such
registration statement to become effective, and, keep such registration
statement effective for a period of up to two years, or such lesser period of
time as all of the Shares have been sold or can be sold without restriction
under Rule 144;

              (ii)  Prepare and file with the SEC such amendments and
supplements to such registration statement and the prospectus used in connection
with such registration statement as may be necessary to comply with the
provisions of the Act with respect to the disposition of all securities covered
by such registration statement;

              (iii) Furnish to each Investor such numbers of copies of a
prospectus, including a preliminary prospectus, in conformity with the
requirements of the Act, and such other documents as they may reasonably request
in order to facilitate the disposition of securities;

              (iv)  Use its best efforts to register and qualify the securities
covered by such registration statement under such other securities or Blue Sky
laws of such jurisdictions as shall be reasonably requested by each Investor;
provided that the Company shall not be required in connection therewith or as a
condition thereto to qualify to do business or to file a general consent to
service of process in any such states or jurisdictions, unless the Company is
already subject to service in such jurisdiction and except as may be required by
the Act;

              (v)   Notify each Investor at any time when a prospectus relating
to such registration statement is required to be delivered under the Act of the
happening of any event as a result of which the prospectus included in such
registration statement, as then in effect, includes an untrue statement of a
material fact or omits to state a material fact required to be stated therein or
necessary to make the statements therein not misleading in the light of the
circumstances then existing; and

              (vi)  Cause all such securities registered pursuant hereunder to
be listed, prior to the date of the first sale of such securities pursuant to
such registration, on each securities exchange on which similar securities
issued by the Company are then listed.

          4.2 Expenses of Registration.  All expenses, other than underwriting
              ------------------------
discounts and commissions, incurred in connection with the requests for
registration pursuant to Section 4.1, including (without limitation) all
registration, filing and qualification fees, printers' and accounting fees, and
fees and disbursements of counsel for the Company shall be borne by the Company.

          4.3 Indemnification.  In connection with the registration statement
              ---------------
required to be filed by the Company pursuant to this Section 4:

              (a) To the extent permitted by law, the Company will indemnify
and hold harmless each Investor, the officers, directors and partners of each

                                       7
<PAGE>

Investor and each Person, if any, who controls any thereof within the meaning of
the Act or the 1934 Act, against any losses, claims, damages, or liabilities
(joint or several) to which they may become subject under the Act or the 1934
Act or other federal or state law, insofar as such losses, claims, damages, or
liabilities (or actions in respect thereof) arise out of or are based upon any
of the following statements, omissions or violations (collectively a
"Violation"): (i) any untrue statement or alleged untrue statement of a material
fact contained in such registration statement, including any preliminary
prospectus or final prospectus contained therein or any amendments or
supplements thereto, (ii) the omission or alleged omission to state therein a
material fact required to be stated therein, or necessary to make the statements
therein not misleading, or (iii) any violation or alleged violation by the
Company of the Act, the 1934 Act, any state securities law or any rule or
regulation promulgated under the Act, or the 1934 Act or any state securities
law; and the Company will pay to each Investor or controlling Person, as
incurred, any legal or other expenses reasonably incurred by them in connection
with investigating or defending any such loss, claim, damage, liability, or
action; provided, however, that the indemnity agreement contained in this
subsection 4.4(a) shall not apply to amounts paid in settlement of any such
loss, claim, damage, liability, or action if such settlement is effected without
the consent of the Company (which consent shall not be unreasonably withheld),
nor shall the Company be liable in any such case to the extent any such loss,
claim, damage, liability or action arises out of or is based upon a Violation
which occurs in reliance upon and in conformity with written information
furnished to the Company in an instrument duly executed by such Investor,
officer, director, partner or controlling Person expressly for use in connection
with such registration.

               (b) To the extent permitted by law, each Investor will indemnify
and hold harmless the Company, each of its directors, each of its officers who
has signed the registration statement, each Person, if any, who controls the
Company within the meaning of the Act, any placement agent, and any controlling
Person of any such placement agent or Investor, against any losses, claims,
damages, or liabilities (joint or several) to which any of the foregoing Persons
may become subject, under the Act, or the 1934 Act or other federal or state
law, insofar as such losses, claims, damages, or liabilities (or actions in
respect thereto) arise out of or are based upon any Violation, in each case to
the extent (and only to the extent) that such Violation occurs in reliance upon
and in conformity with written information furnished to the Company in an
instrument duly executed by such Investor expressly for use in connection with
such registration; and each Investor will pay, as incurred, any legal or other
expenses reasonably incurred by any Person intended to be indemnified pursuant
to this Section 4.4(b), in connection with investigating or defending any such
loss, claim, damage, liability, or action; provided, however, that the indemnity
agreement contained in this Section 4.4(b) shall not apply to amounts paid in
settlement of any such loss, claim, damage, liability or action if such
settlement is effected without the consent of such Investor, which consent shall
not be unreasonably withheld; provided, that, in no event shall any indemnity
under this Section 4.4(b) exceed the gross proceeds from the offering received
by such Investor.

               (c) Promptly after receipt by an indemnified party under this
Section 4.4 of notice of the commencement of any action (including any
governmental

                                       8
<PAGE>

action), such indemnified party will, if a claim in respect thereof is to be
made against any indemnifying party under this Section 4.4, deliver to the
indemnifying party a written notice of the commencement thereof and the
indemnifying party shall have the right to participate in, and, to the extent
the indemnifying party so desires, jointly with any other indemnifying party
similarly noticed, to assume the defense thereof with counsel mutually
satisfactory to the parties; provided, however, that an indemnified party
(together with all other indemnified parties which may be represented without
conflict by one counsel) shall have the right to retain one separate counsel,
with the fees and expenses to be paid by the indemnifying party, if
representation of such indemnified party by the counsel retained by the
indemnifying party would be inappropriate due to actual or potential differing
interests between such indemnified party and any other party represented by such
counsel in such proceeding. The failure to deliver written notice to the
indemnifying party within a reasonable time of the commencement of any such
action, if prejudicial to its ability to defend such action, shall relieve such
indemnifying party of any liability to the indemnified party under this Section
4.4, but the omission so to deliver written notice to the indemnifying party
will not relieve it of any liability that it may have to any indemnified party
otherwise than under this Section 4.4.

               (d) If the indemnification provided for in this Section 4.4 is
held by a court of competent jurisdiction to be unavailable to an indemnified
party with respect to any loss, liability, claim, damage, or expense referred to
therein, then the indemnifying party, in lieu of indemnifying such indemnified
party hereunder, shall contribute to the amount paid or payable by such
indemnified party as a result of such loss, liability, claim, damage, or expense
(or actions in respect thereof) in such proportion as is appropriate to reflect
the relative fault of the indemnifying party on the one hand and of the
indemnified party on the other in connection with the statements or omissions
that resulted in such loss, liability, claim, damage, or expense (or actions in
respect thereof) as well as any other relevant equitable considerations. The
relative fault of the indemnifying party and of the indemnified party shall be
determined by reference to, among other things, whether the untrue or alleged
untrue statement of a material fact or the omission to state a material fact
relates to information supplied by the indemnifying party or by the indemnified
party and the parties' relative intent, knowledge, access to information, and
opportunity to correct or prevent such statement or omission. The Company and
each Investor agree that it would not be just and equitable if contribution
pursuant to this Agreement were determined by pro-rata allocation or by any
other method of allocation which does not take account of the equitable
considerations referred to above. The amount paid or payable by an indemnified
party as a result of the losses, claims, damages or liabilities (or actions in
respect thereof) referred to above shall include any legal or other expenses
reasonably incurred by such indemnified party in connection with investigating
or defending any such action or claim.

               (e) The obligations of the Company and Investor under this
Section 4.4 shall survive the completion of any offering of securities in a
registration statement under this Section 5, and otherwise.

                                       9
<PAGE>

     5.  Conditions of Each Investor's Obligations at Closing.  The obligations
         ----------------------------------------------------
of each Investor under subsection 1.2 of this Agreement are subject to the
fulfillment on or before the applicable Closing of each of the following
conditions, the waiver of which shall not be effective without each Investor's
consent thereto:

          5.1 Representations and Warranties. The representations and warranties
              ------------------------------
of the Company contained in Section 2 shall be true on and as of the applicable
Closing with the same effect as though such representations and warranties had
been made on and as of the date of such Closing.

          5.2 Performance. The Company shall have performed and complied with
              -----------
all agreements, obligations and conditions contained in this Agreement that are
required to be performed or complied with by it on or before the applicable
Closing.

          5.3 Qualifications. All authorizations, approvals, or permits, if any,
              --------------
of any governmental authority or regulatory body of the United States or of any
state that are required in connection with the lawful issuance and sale of the
Securities pursuant to this Agreement shall be duly obtained and effective as of
the applicable Closing.

          5.4 Proceedings and Documents. All corporate and other proceedings in
              -------------------------
connection with the transactions contemplated at the applicable Closing and all
documents incident thereto shall be reasonably satisfactory in form and
substance to Investor, and it shall have received all such counterpart original
and certified or other copies of such documents as it may reasonably request.

          5.5  Warrants.  The Company shall execute and deliver the Warrants.
               --------

          5.6 Opinion of Company Counsel. The Investors shall have received an
              --------------------------
opinion from counsel to the Company in form and substance reasonably
satisfactory to the Investors.

     6. Conditions of the Company's Obligations at Closing. The obligations
        --------------------------------------------------
of the Company to each Investor under this Agreement are subject to the
fulfillment on or before the applicable Closing of each of the following
conditions by each Investor:

          6.1 Representations and Warranties. The representations and warranties
              ------------------------------
of Investors contained in Section 3 shall be true on and as of the applicable
Closing with the same effect as though such representations and warranties had
been made on and as of the Closing.

          6.2 Payment of Purchase Price. Each Investor shall have delivered the
              -------------------------
purchase price specified in Section 1.

          6.3 Qualifications. All authorizations, approvals, or permits, if any,
              --------------
of any governmental authority or regulatory body of the United States or of any
state that

                                       10
<PAGE>

are required in connection with the lawful issuance and sale of the Securities
pursuant to this Agreement shall be duly obtained and effective as of the
applicable Closing.

     7.  Miscellaneous.
         -------------

          7.1 Survival of Warranties. The warranties, representations and
              ----------------------
covenants of the Company and Investor contained in or made pursuant to this
Agreement shall survive for one year after the execution and delivery of this
Agreement and the Initial Closing.

          7.2 Assignment; Successors and Assigns. No provision of this Agreement
              ----------------------------------
may be assigned (other than to an affiliate of any Investor), without the prior
written consent of the other parties hereto.  Except as otherwise provided
herein, the terms and conditions of this Agreement shall inure to the benefit of
and be binding upon the respective successors and assigns of the parties
(including transferees of any Securities).  Nothing in this Agreement, express
or implied, is intended to confer upon any party other than the parties hereto
or their respective successors and assigns any rights, remedies, obligations, or
liabilities under or by reason of this Agreement, except as expressly provided
in this Agreement.

          7.3 Governing Law. This Agreement shall be governed by and construed
              -------------
under the laws of the State of New York as applied to agreements among
California residents entered into and to be performed entirely within
California.

          7.4 Counterparts. This Agreement may be executed in two or more
              ------------
counterparts, each of which shall be deemed an original, but all of which
together shall constitute one and the same instrument.

          7.5 Titles and Subtitles. The titles and subtitles used in this
              --------------------
Agreement are used for convenience only and are not to be considered in
construing or interpreting this Agreement.

          7.6 Notices, etc. All notices and other communications required or
              ------------
permitted hereunder shall be in writing and shall be sent by personal delivery,
facsimile, overnight courier or mailed by certified or registered mail, postage
prepaid, return receipt requested, to the facsimile number or address as
follows:

     Company:

     Applied Imaging Corp.
     2380 Walsh Avenue, Building B
     Santa Clara, CA 95051
     Facsimile:  (408) 562-0264
     Attention:  President

                                       11
<PAGE>

     with a copy to:

               Georgopoulos Pahlavan & Prince, LLP
               935 Hamilton Avenue
               Menlo Park, CA 94025
               Facsimile:  (650) 473-9060
               Attention:  Paul G. Prince

     Investors:

               To the facsimile number or address for each respective Investor
               set forth in Schedule I hereto.
                            ----------

     Placement Agent:

               H.C. Wainwright & Co., Inc.
               One Boston Place
               Boston, MA 02108
               Facsimile:  617-788-9520
               Attention:  Edward P. Crouch, Managing Director and
                           Anne Buckley, Counsel

or to such other facsimile number or address provided to the parties to this
Agreement in accordance with this Section 7.6. Such notices or other
communications shall be deemed delivered upon receipt, in the case of overnight
delivery, personal delivery or facsimile transmission (as evidenced by the
confirmation thereof), or 3 days after deposit in the mails (as determined by
reference to the postmark).

          7.7 Finder's Fee. Except for H.C. Wainwright & Co., Inc., no Person
              ------------
has, or as a result of the transactions contemplated herein will have, any right
or valid claim against the Company or the Investor for any commission, fee or
other compensation as a finder or broker, or in any similar capacity based upon
obligations incurred by the Company.

          7.8 Expenses. Irrespective of whether any Closing is effected, each
              --------
party shall pay all costs and expenses that it incurs with respect to the
negotiation, execution, delivery and performance of this Agreement. If any
action at law or in equity is necessary to enforce or interpret the terms of
this Agreement, the prevailing party shall be entitled to reasonable attorney's
fees, costs and necessary disbursements in addition to any other relief to which
such party may be entitled.

          7.9 Amendments and Waivers. Any term of this Agreement may be amended
              ----------------------
and the observance of any term of this Agreement may be waived (either generally
or in a particular instance and either retroactively or prospectively), only
with the written consent of the Company and Investor. Any amendment or waiver
effected in accordance with this paragraph shall be binding upon each holder of
any securities

                                       12
<PAGE>

purchased under this Agreement at the time outstanding (including securities
into which such securities are convertible), each future holder of all such
securities, and the Company.

          7.10 Severability. If one or more provisions of this Agreement are
               ------------
held to be unenforceable under applicable law, such provision shall be excluded
from this Agreement and the balance of the Agreement shall be interpreted as if
such provision were so excluded and shall be enforceable in accordance with its
terms.

          7.11 Entire Agreement. This Agreement and the documents referred to
               ----------------
herein constitute the entire agreement among the parties and no party shall be
liable or bound to any other party in any manner by any warranties,
representations, or covenants except as specifically set forth herein or
therein.


                            [Signature Page Follows]

                                       13
<PAGE>

     IN WITNESS WHEREOF, the parties have executed this Agreement as of the date
first above written.


                                           COMPANY:

                                           APPLIED IMAGING CORP.



                                           By _____________________________
                                              Name:
                                              Title:

                                       14
<PAGE>

     IN WITNESS WHEREOF, the parties have executed this Agreement as of the date
first above written.



                                           INVESTORS:

                                           [NAME OF INVESTOR]




                                           By _____________________________
                                              Name:
                                              Title:

                                       15