The cryopreserved stocks are pathogen free and can be recovered pathogen free. Cryopreservation is safely done for an indefinite time so stocks can be preserved from the effects of genetic drift. The cost of cryopreserving a stock is often less than the annual cost of maintaining the stock on the shelf. For two decades The Jackson Laboratory has maintained and managed a successful cryopreservation program. Inbred and mutant stocks of mice have been routinely frozen and recovered from the world's largest resource of frozen embryos.
Many strains have limited and infrequent demand.
It is not practical to maintain strains as actively breeding colonies if the demand is only occasional. We do, however, make the strains available when needed for research purposes. Upon receipt of an order, mice from cryopreserved strains can be recovered from frozen embryos or sperm. It usually takes up to 6 months, depending on the genotype of the embryos or sperm and reproduction capability of the strain to re-establish a sufficiently sized breeding colony from which mice of the desired genotype can be distributed. Maintained properly in liquid nitrogen containers it is believed that embryos and sperm can be safely stored for centuries.