Genetic structure of sheep of different breeds of Siberian and Far Eastern Region

Abstract

The research goal was comparative evaluation of the genetic structure of sheep of Siberian and Far Eastern region using the genes GDF9/G1, CAST, KRT1.2, and KAP1.3. The following 5 sheep breeds were studied: Trans-Baikal breed of the Khangil type (ТBKh), Kulunda fine-wool breed (KUL), West Siberian mutton breed (WSM), Aginskaya breed of the Zugalay type (AGZ), and the Buubei breed (BUB); the similarities and differences between the breeds were determined, population and genetic characteristics of the herds were given, their differentiation and phylogenetic relationships were defined. It was found that in all sheep breeds, the prevailing genotypes were GDF9/G1^GG and CAST^MM, with rare alternative genotypes GDF9/G1^AA and CAST^NN. All breeds, with the exception of WSM, were characterized by a high frequency of the KRT1.2^MM genotype (more than 74%). Regarding the ratio of genotypes in the KAP1.3 gene, the breeds had variability. The highest frequency of the KAP1.3^XX genotype (61.0%) was found in the ТBKh breed, the lowest - in the BUB (26.7%). Of all the studied breeds, the WSM has the most original profile. It is distinguished by a reduced frequency of the GDF9/G1^GG genotype by 22.6-25.6%, CAST^MM - by 10.0-21.2%, KRT1.2^MM - by 40.7-62.5% as compared to other breeds. The gene balance in the herds is not disturbed, χ2 is in the range of 0.0007-1.1335; the level of expected heterozygosity coincides with the observed one. The coefficient of homozygosity (Ca) in breeds varies from 60.1 to 69.9%; number of effective alleles (Naj) - 2.47-3.27; level of polymorphism (PIC) - 0.193-0.389. The highest genetic similarity index (r) was found between AGZ and KUL (0.992), the lowest - 0.858, between the BUB and WSM breeds. Cluster analysis showed that KUL, AGZ and BUB form two adjacent clusters, and the most distant from all breeds is WSM.