JOINDER AGREEMENT

                  This Joinder  Agreement (the  "JOINDER") is entered into as of
June 29, 2000 by and among COGENE BIOTECH VENTURES, L.P. (the "NEW NON-PREFERRED
HOLDER") and INFORMAX, INC., a Delaware corporation (the "COMPANY").

                  WHEREAS,  the  non-preferred  holders of the  Company  who are
listed on the  signature  pages of the  Non-Preferred  Holder  Rights  Agreement
(collectively, the "NON-PREFERRED HOLDERS") and the Company, are parties to that
certain  Non-Preferred  Holder  Rights  Agreement  dated  March  29,  2000  (the
"NON-PREFERRED AGREEMENT");

                  WHEREAS, pursuant to a Stock Purchase Agreement dated June 29,
2000 by and  between  the New  Non-Preferred  Holder  and the  Company,  the New
Non-Preferred  Holder acquired shares of non-voting  common stock of the Company
(the "STOCK PURCHASE AGREEMENT"); and

                  WHEREAS,  a condition to the  obligations of the parties under
the Stock  Purchase  Agreement is that the New  Non-Preferred  Holder  becomes a
party  to the  Non-Preferred  Agreement  concurrently  with  the  execution  and
delivery of the Stock Purchase Agreement.

                  NOW,  THEREFORE,  in consideration of the premises,  and other
good and valuable consideration,  the receipt and sufficiency of which is hereby
acknowledged, each of the New Non-Preferred Holders and the Company hereby agree
as follows:

                  1. The New Non-Preferred  Holder is hereby made a party to the
Non-Preferred  Agreement as a "Non-Preferred  Holder" in accordance with Section
4.11 thereunder,  and the New Non-Preferred  Holder hereby agrees to be bound by
all the terms and conditions of the Non-Preferred  Agreement as a "Non-Preferred
Holder"  thereunder.  The terms and  conditions of the  Non-Preferred  Agreement
shall apply to the shares of  nonvoting  common stock  acquired  pursuant to the
Stock Purchase Agreement.

                  2. The New Non-Preferred Holder represents and warrants to the
Company and the other Non-Preferred  Holders that the New Non-Preferred  Holder:
(a) has  reviewed  the  Joinder and the  Non-Preferred  Agreement  (as  attached
hereto) in their entireties, and fully understands all provisions of the Joinder
and the  Non-Preferred  Agreement,  and (b) in accordance  with the terms of the
Non-Preferred  Agreement the New Non-Preferred Holder has become a Non-Preferred
Holder  under  the  Non-Preferred  Agreement  and is bound by all the  terms and
conditions of the Non-Preferred Agreement with the same effect as though the New
Non-Preferred Holder was a subscribing party to the Non-Preferred Agreement.

                  3.  All   references   in  the   Non-Preferred   Agreement  to
"Non-Preferred Holder" or "Non-Preferred Holders" shall be deemed to include the
New Non-Preferred Holder.

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                  4.  All of  the  terms  and  conditions  of the  Non-Preferred
Agreement are  unmodified  and shall continue in full force and effect and shall
be binding upon the parties  hereto and their  respective  assigns in accordance
with the terms thereof.

                  5. This Joinder may be executed  (including  by  facsimile) in
one or more  counterparts,  each of which shall be deemed an original but all of
which together will constitute one and the same instrument.

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

                                        COMPANY

                                        INFORMAX, INC.

                                        By: /s/ ALEX TITOMIROV
                                            ---------------------------------
                                            Name:  Alex Titomirov
                                            Title: Chairman/CEO



                                        NEW NONPREFERRED HOLDERS

                                        COGENE BIOTECH VENTURES, L.P.

                                        BY:  COGENE BIOTECH VENTURES GP, L.L.C.,
                                             ITS GENERAL PARTNER

                                        By:    /s/ SCOTT E. SCHWINGER
                                              ---------------------------------
                                              Name:   Scott E. Schwinger
                                              Title:  Vice President

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