GENETIC-STRUCTURE OF SOME NATIVE AND COMM ERCIAL BREEDS OF CATTLE (BOS-TAURUS) FROM EURASIA

On the basis of polymorphism of genes, controlling seven blood and fou r milk proteins, genetic structure and main variation parameters were analyzed in 27 breeds of cattle, II of which were native. Difference i n allele frequencies of blood proteins were detected in the Jersey (is land form) and Yakut (geographically isolated form) breeds; in milk pr oteins, the Yaroslavl' breed differed from the other breeds. Native br eeds generally had a:more specialized genetic structure than commercia l breeds. They had a greater deficit of heterozygotes, which is probab ly related to the small number of individuals in this breed group and their high homozygosity. An analysis of inter- and intrapopulation div ersity showed differences in groups of commercial and native breeds th at depended on the intensity of selection in populations.