Abstract

Over many centuries, genetic selection of sheep for particular meat and wool traits has made steady progress andgiven producers the opportunity to choose from a broad spectrum of well defined breeds. Selection for specific features ofbody frame or fleece has resulted in the emergence of true “meat” breeds (e.g. Poll Dorset, Suffolk, Texel) and other breedshighly valued for their fleece characteristics (e.g. Merino, Romney). Whilst such selection tends toward the outer limits ofgenetic variation among sheep, the sheep genome itself and natural mutation rates provide an inbuilt restriction to geneticchange and the appearence of new phenotypic varieties. In comparison, the use of transgenesis to add specific functionalsheep or non-sheep genes to the sheep genome has the potential to greatly expand the phenotypic range possible amongsheep. For example, in a preliminary sheep transgenesis experiment using a cortical type II keratin intermediate filamenttransgene, we have shown it is possible to alter fibre structure and properties. The fact genes from any species may be usedin the transgenesis process provides many experimental options simply not possible using the sheep genome alone. Thispaper is a discussion of some of the recent attempts to modify the genotype / phenotype of wool producing breeds usingtransgenesis. In particular, results of the earliest programmes designed to modify wool fibre properties and fibre growth rates are reviewed.

CS, Bawden, NM Penno, CJ McLaughlan, SK Walker, PI Hynd, and GE Rogers

Proceedings of the New Zealand Society of Animal Production, Volume 60, Hamilton, 147-154, 2000