Intrapopulation genetic differentiation of bulls of the Kholmogory breed in the Komi Republic by microsatellites

The polymorphism of microsatellites was studied in 85 bulls – semen donors of the following breeds and types: the Kholmogory breed (38), the Holstein breed (10), the Pechora type of the Kholmogory breed (17), and the type obtained through crossing the Pechora type with the typical Kholmogory breed (20). Individuals were genotyped by 15 microsatellite loci. The largest number of specific alleles was revealed in the group of the Kholmogory breed bulls. The maximum genetic distance was identified between the Pechora-Kholmogory bulls and the Holstein bulls (DN 0.237, FST 0.045). The division of the entire array into two clusters in the program Strukture confirmed the high genetic differentiation between the crossed and purebred Pechora type bulls of the Kholmogory breed and the Holstein breed. The genetic difference between the Holstein and the typical Kholmogory breed was as high. The average probability of membership in the first cluster was 0.107±0.039, in the second cluster – 0.893±0.039 for Holstein bulls, 0.828±0.052 and 0.172±0.052 for Pechora type bulls of the Kholmogory breed, 0.860±0.019 and 0.140±0.019 for Pechora-Kholmogory bulls, and 0.633±0.046 and 0.367±0.046 for bulls of the typical Kholmogory breed, respectively. Information on number of effective alleles per locus, heterozygosity and fixation indices in animal groups of different genealogy and breeds did not provide any reliable and significant information on their intrapopulation genetic structure and differentiation that could be used in practical work to maintain the genetic diversity and reproduce the conserved gene pool of the breed. The cluster analysis at k=3 and k=4 allowed to identify and detail the structure and degree of genetic difference between groups and, thus, obtain additional information for planning and implementing gene pool conservation measures.