ABSTRACT
The quality of animals has improved due to better management and genetic selection. The use of artificial insemination has contributed significantly to the genetic improvement of farm animals. Nuclear transfer probably holds more promise for obtaining identical offspring than does cloning. Nuclear fusion implies the union of nuclei from two gametes, which are either eggs or sperm. In vitro fertilization has received widespread attention and interest since the first human resulting from the procedure was born in England. Initial attempts in livestock were largely unsuccessful because scientists tried to recover eggs near the time of ovulation. Recombinant DNA technology is receiving widespread attention and research funding. Introduction of mammalian genes for various proteins, e.g., insulin, has resulted in bacteria manufacturing insulin as a by-product. Culture media necessary for embryo survival were developed. All of these procedures will be used extensively to take embryos to the new frontiers: sexing, freezing, and cloning.
