Characterization of the genetic diversity of modern and archival populations of Black-and-White cattle using microsatellite markers
Among Russian dairy cattle breeds, Black-and-White is the most common. Stud bulls of Holstein breed are actively used to increase its productivity. This leads to the loss of allelic combinations characteristic for Black-and-White breed. The purpose of the study was to compare the gene pools of the modern Black-and-White cattle population with animals of the same breed used 30-40 years ago, as well as with modern animals of Holstein breed. The material used for the study was ear pluck, blood, and semen from cattle of modern Russian populations of Black-and-White (BLWT, n = 25) and Holstein (HLST, n = 19) breeds, as well as of animals of Black-and-White breed (BLWT_OLD, n = 13), preserved in the genetics bank, which were previously used in breeding. The groups of 10 animals were genotyped by STR markers using a multiplex panel (microsatellite loci). Amplification products were analyzed by capillary electrophoresis on 3130xl Genetic DNA-Analyzer. The results were statistically processed and visualized using the software environment R 3.5.0 with additional software. Cluster analysis showed the differentiation of the HLST population from BLWT and BLWT_OLD. The high observed (Ho = 0.721 ± 0.036) and expected heterozygosity (He = 0.713 ± 0.026), as well as BLWT allelic diversity (Ar = 5.689 ± 0.395) indicate the long-term breeding work in Holstein cattle. At some BLWT loci, the alleles characteristic of BLWT_OLD disappeared, whereas the alleles found in HLST appeared. Genetic distance (Fst) decreased from 0.099 between BLWT_OLD and HLST to 0.055 between BLWT and HLST Breeding work aimed not only at increasing productivity but also at maintaining biodiversity, will help preserve the allelic combinations characteristic of Black-and-White breed and distinguishing it from other dairy cattle breeds.