Investigation of local cattle breeds of the Republic of Dagestan using different types of DNA markers

Mountain cattle and Caucasian Brown breed bred on the territory of the Republic of Dagestan are valuable genetic resources due to their adaptive abilities. The analysis of genetic diversity using STR- and SNP-markers made it possible to estimate allelic diversity and the level of heterozygosity, as well as to study the population structure of these breeds and the relationship with other breeds. Analysis of genetic diversity by STR- and SNP-markers revealed a significant lack of heterozygotes in Mountain cattle (0,057 and 0,020). The highest allelic diversity in STR markers was detected in Mountain cattle (9,241), for SNP – in the Caucasian type of Brown Swiss breed (1,991). Principal component analysis (PCA) was performed to assess interbreed relationships. The PCA analysis by STR markers showed that Mountain cattle and Caucasian Brown breed form relatively independent clusters overlapping with the Brown Swiss breed. The PCA analysis by SNP markers allowed a clearer separation of the populations. Analysis of the structure of the genetic network by STR- and SNP-markers showed a common origin between Mountain cattle and the Caucasian type of Brown Swiss. Cluster analysis of the studied populations was carried out with the number of clusters ranging from 2 to 5. The optimal number of clusters is 4. According to STR-markers at K = 2, the Mountain cattle differentiated from other studied groups. At K= 3, the Caucasian Brown breed is distinguished to a separate cluster. When the number of clusters increases up to five, there is a division into two subgroups within the Mountain cattle. According to SNP-markers, at K= 2, the Brown Swiss is separated from other investigated groups. When the number of clusters increases up to five, two subgroups with different genetic components are distinguished in the Caucasian brown breed.