ABSTRACT
Cryopreservation of mammalian embryos has been greatly improved since successful freezing was first reported for mice. The use of cryopreserved fertilized eggs, as for the generation of transgenic mice, also enables efficient production of other transgenic large domestic animals. The rate of in vitro development of vitrified, microinjected eggs to the two-cell stage appeared to be decreased compared with that of the unvitrified, microinjected eggs. However, 17–19% of the transferred eggs developed into live young, with no difference in efficiency of development into live young between the vitrified and unvitrified eggs after injection and subsequent transfer. This chapter describes the successful use of cryo-preserved pronucleate stage eggs to generate transgenic animals. It enables efficient and convenient production of transgenic animals particularly in conditions in which space for animal breeding and manpower are markedly limited.
