Sperm Cryopreservation

GEC offers sperm cryopreservation of individual mouse strains housed at Yale University. Strains will be cryopreserved in the order in which requests are submitted. Please read the following information carefully to understand the benefits and limitations of cryopreservation.

Provision of Animals

Three males between 2 and 5 months of age should be clearly marked for sperm cryopreservation in your animal facility. It is preferred, but not required that the males have demonstrated fertility in vivo and if that information is known it should be included on the "Sperm Cryopreservation Order Form".

Cryopreservation

We request 3 males, 2 months to 5 months of age, from which we will cryopreserve sperm. A sample of thawed sperm from each strain will be used in IVF to verify the ability of the sperm to fertilize post-thaw. Results will be noted as percent that cleave to 2 cell stage and will be sent to the investigator. Each request offers the option of transferring the 2 cell embryos to a pseudopregnant female and allowing development to term for an additional fee.

Other Considerations

The option to cryopreserve embryos versus sperm should be carefully considered. On the front-end cryopreservation of sperm is significantly less costly than embryos. On the back-end, however, if you revive the line in the future it is more expensive to do so from cryopreserved sperm than embryos so that the degree of price difference is offset if recovery of the line is contemplated. In addition one should realize that cryopreserved sperm will be used with wildtype oocytes of the same strain for recovery. Therefore instances where homozygosity or a mixed strain background needs to be preserved should use embryos. Also if there is more than one genetic alteration in the line embryo cryopreservation would likely be less costly if extended breeding an genotyping will be required after recovery from frozen sperm.