PROSPECTS FOR BIOTECHNOLOGY IN ANIMAL PRODUCTION

Abstract

Through recent advances in molecular and reproductive biology selected genes from one animal or species can be inserted into another animal's genome to produce a 'transgenic' animal. Striking increases have been achieved in the rate of growth of mice containing additional copies of the rat growth hormone gene. Such results raised the possibility of using similar techniques to modify the expression of existing genes and introduce novel gene(s) into domestic livestock for improved productivity. The introduction of multiple copies of the growth hormone genes into pig embryos has resulted in live births of pigs that grew 10-20X larger and reached market weight three weeks earlier than litter-mates. The introduced genes were passed from generation to generation. In sheep cysteine supplementation into the abomasum produced at 10.20% increase in wool growth rate. Genes responsible for cysteine biosynthesis have been isolated from yeast, and a modified gene suitable for expression in sheep produced. By engineering the cysteine biosynthetic pathway into the sheep genome there is scope to considerably increase wool production. Keywords: gene transfer, transgenesis. recombinant DNA, embryo manipulation.