Plant & Animal Genome VI Conference

W24,P330

GENOTYPING ON AN EQUINE FULL-SIB FAMILY FOR LINKAGE MAP DEVELOPMENT

1. Animal Health Trust, Lanwades Park, Kennett, Suffolk, CB8 7PN
2. TBA Equine Fertility Unit, Mertoun Paddocks, Woodditton Road, Newmarket, Suffolk CB8 9BH, UK
3. Division of Immunogenetics, Institute for Animal Breeding, University of Berne, Bremgartenstrasse 109a, CH-3012 Berne, Swizerland

A full-sibling horse family has been generated in order to efficiently develop a genetic map of the horse. This has been made possible by the production of two pairs of identical twin mares by embryo splitting. These mares were repeatedly covered by Thinur, an Icelandic stallion, and the resulting foetuses aborted at 30 days. This has allowed the rapid generation of a large pedigree of full-sibling progeny. To date the pedigree consists of 5 grandparents, 5 parents and 41 progeny. A total of 208 microsatellite markers were tested on the stallion and mares for amplification and polymorphism. Of these 174 (84%) gave clear results and 124 (60%) were considered sufficiently polymorphic in the parents to be used for genotyping across the whole family. The results of this genotyping work show that this pedigree is a powerful tool in the generation of linkage groups. Several small groups of linked markers have been unequivocally ordered. In addition, the inclusion of cosmid-derived microsatellites has allowed the positioning of several small linkage groups onto specific chromosomes.