Genetic relationships among Å umava, Valachian and Improved Valachian sheep

This study compares the genetic variation in three breeds native in the territory of the Czech and Slovak Republics. Six polymorphic microsatellite loci and the loci of beta-lactoglobulin and prolactin are used to detect differences in polymorphism of these markers in Å umava sheep, Valachian sheep and Improved Valachian sheep breeds. The differences among three reproductively isolated sheep populations, in the frequencies of beta-lactoglobulin as well as prolactin alleles, are likely caused by drift in small closed populations. The lower numbers of alleles in MAF33 and MAF209 loci, found in Valachian sheep, are probably due to a dramatic reduction of the population size of this rare breed in the past. Relatively high heterozygosity, in majority of the investigated loci, is a useful tool for maintaining these small populations in the Animal Resources Programme.