MICROSATELLITE DNA VARIATION WITHIN AND AMONG EUROPEAN CATTLE BREEDS

Microsatellite markers offer great potential for genetic comparisons w ithin and between populations. We report the analysis of 12 microsatel lite loci in six breeds of European cattle. This yielded a wide spectr um of variability with observed heterozygosities ranging from 0.00 to 0.91. Deviations from Hardy-Weinberg equilibrium were noted for some l ocus-population combinations, particularly at a microsatellite located within the prolactin gene. Also, significant linkage disequilibrium w as detected between two microsatellite loci located within the bovine major histocompatibility complex, and this association was maintained across breeds, providing evidence for marker stability during short-te rm evolution. The mode of mutation was investigated by comparing the o bserved data with that expected under the infinite alleles model of ne utral mutation, and six of the microsatellite loci were found to devia te significantly, suggesting that a stepwise mutation model may be mor e appropriate. One indication of marker utility is that, when genetic distance estimates were computed, the resultant dendrogram showed conc ordance with known breed histories.