GENETIC DIVERSITY OF MITOCHONDRIAL DNA HAPLOGROUPS IN THE DON HORSE BREED

Abstract

The Don breed of horses, which became famous in Russia already in the middle of the 18th century, was obtained by long-term crossing of nomadic horses with cultured oriental breeds. Due to the reduction in the number of Don queens to 200 broodmares, the research of the genetic characteristics of this breed is of particular relevance. The purpose of the research was to study the matrilineal structure of the Don horse breed based on phylogenetic analysis of 530 nucleotide pairs [n.p.] of the hypervariable section of the D-loop of mitochondrial DNA [mtDNA] in 26 mares representing the main female families. Analysis of the mtDNA sequence was performed using the Neighbor-Joining [NJ] method in combination with bootstrap analysis in the MEGA7 software. In the mitochondrial genomes of the tested Don horses, 26 different haplotypes were identified, which are part of 10 mtDNA haplogroups, including A, B, D, G, L, M, N, O, P, and Q, according to the modern classification. Additionally, four new haplogroups were identified, leading the line from Black Sea mares and atypical for most European breeds. The sequenced fragment of the D-loop from 15471 to 16000 n.p. included 115 polymorphic sites, mainly represented by transversions. The mtDNA structure of the Don breed was dominated by haplogroups G (19.2%), B (15.4%), and L (11.5%). All the analyzed uterine families were clearly differentiated at the level of haplogroups and haplotypes with a high bootstrap support rate (58%–100%). This indicates a high genetic diversity of the genealogical matrilineal structure of the Don horse breed.