DETERMINATION OF SEX AND CHIMERISM IN THE DOMESTIC SHEEP BY DNA AMPLIFICATION USING HMG-BOX AND MICROSATELLITE SEQUENCES

We describe a rapid, reliable method for the sexing of the domestic sh eep (Ovis aries) by amplification of Y-chromosome-specific sequences i n male genomic DNA using the polymerase-chain reaction (PCR). Oligonuc leotide primers were selected from a conserved sequence, the HMG box, in the sequence of ovine Sry, permitting amplification of a defined 16 1 bp fragment only from male-specific genomic DNA. As a control, micro satellite primers also were used in PCR reactions, recognising a seque nce that is amplifiable in genomic DNA from both males and females. In addition, we demonstrate the feasibility of using this technique for the detection of Y-specific sequences in foetal biopsies (specifically small numbers of foetal germ cells), and in reconstruction mixtures o f male and female genomic DNA to simulate the analysis of intersex chi maeras which would be produced when pluripotent cells have been establ ished for this species.