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                                                                   EXHIBIT 21

                              List of Subsidiaries
                              --------------------

SUBSIDIARY:                                      STATE OF INCORPORATION:

BioDevelopment Laboratories, Inc.                Delaware

Genzyme Transgenics Securities Corporation       Massachusetts

TSI Corporation                                  Delaware 

Transgenics Investments, Inc.                    Delaware 

TSI Premium Foods, Inc.                          Delaware 

TSI Washington Laboratories, Inc.                Delaware 

TSI Holdings, Inc.                               Delaware 

The TSI Center For Diagnostic Products, Inc.     Massachusetts

Argus Research Laboratories, Inc.                Delaware 

The Center For Photobiology at Argus, Inc.       Delaware 

TSI Mason Laboratories, Inc.                     Massachusetts

TSI Redfield Laboratories, Inc.                  Arkansas

Health and Sciences Research Incorporated        Delaware 

International Drug Development Corporation       New York