Addendum: Important Events and Advances Since the Workshop
Since March, 1993, the proliferation of new genetically altered mice has continued apace, and the issues of availability and preservation of new strains have been widely discussed. In the fall of 1993, the National Center for Research Resources of the NIH established a national resource for transgenic and targeted-mutant mice at the Jackson Laboratory. This national resource will serve as a repository for genetically altered mouse embryos, will provide these mice to the scientific community, and will conduct research on cryopreservation methods. The program, known as the Induced Mutant Resource, has received additional financial support from the Howard Hughes Medical Institute, the American Cancer Society, the March of Dimes Birth Defects Foundation, the Cystic Fibrosis Foundation, and the American Heart Association. In the 18 months since its inception, the resource has accepted 54 mutant stocks for distribution. Over one-third are available now for distribution.
Since the workshop was held, two comprehensive papers have been published describing the successful cryopreservation of mouse sperm. In both, frozen and thawed sperm have been used for in-vitro fertilization of mouse oocytes and yielded embryos that, after transfer into recipients, developed into live young. That normal pups were produced from cryopreserved sperm of six strains suggests the general applicability of the procedures.
A Request for Applications (RFA) for research into cryopreservation of sperm has been issued by the National Institute of Child Health and Human Development of the National Institutes of Health, and three groups have been funded to pursue this avenue of research.