Viable offspring derived from cryopreserved haploid rabbit parthenotes

The female parthenogenetic haploid embryos can be stored long-term by cryopreservation. Briefly, rabbit haploid parthenotes at the 32-cell stage were produced by electroactivation and in vitro culture. At this embryonic stage, parthenotes were individually cryopreserved by a slow-freezing procedure. After thawing, every embryo was disaggregated and blastomeres used as haploid maternal donors of nuclei. These nuclei were transferred to androgenetic haploid hemizygotes, obtained by female pronuclear removal offertilizedova. In the firstexperiment, 38 out of 87 reconstructedheteroparental diploid zygotes reachedthe hatched blastocyst stage invitro. In the second experiment, ourpurpose was toobtain live pups from each frozen-thawed parthenote. Viable offspring (at least one live pup at delivery) were obtained from five out of seven frozen-thawed haploid morula used as donors, with three live hemiclones being the highest number of pups produced from a single thawed parthenote. These results indicate that the rabbit female gametic endowment can be successfully stored by cryopreservation of parthenogenetic haploid embryos.