Cryoconservation--archiving for the future.

Mouse genetics is set to play a pivotal role in the key post-genome challenge—the study of mammalian gene function. Addressing this challenge will involve the development and application of systematic mutagenesis approaches. The expanding mouse mutant resource that will result threatens to overwhelm the currently available animal facility space. Cryopreservation of both mouse embryos and spermatozoa is currently widely employed for the efficient archiving of mouse stocks. Distribution and dissemination of new and existing mouse strains is simplified by the availability of extensive frozen archives. Also, the availability of archives of frozen spermatozoa provides a potential powerful route for the production of backcross progeny for rapid genetic mapping. Moreover, frozen oocytes and ovaries may offer a valuable addition to the current cryopreservation approaches. Comprehensive mouse mutant archives will provide an essential resource for mammalian genetics throughout the 21st century.