The influence of crossbreeding on genetic structure of the Orlov Ttrotter breed

Abstract

The aim of the study was to investigate the nature of changes in the genetic structure of the Orlov Trotter breed under the influence of the introductory crossbreeding used in the 60s of the 20th century. We analyzed the results of the genotyping of 6700 trotters registered in the Stud Book of the Orlov Trotter breed on 16 microsatellite loci. The differences between the descendants of purebred and crossbred Orlov Trotter horses were determined by the level of polymorphism and heterozygosity. It was found that in the group of Orlov Trotters pedigree of which did not contain ancestors of other breeds, the expected heterozygosity (He=0.709) was slightly higher than the observed heterozygosity (Ho=0.707) with a positive value of the inbreeding coefficient (Fis=0.004). In all groups of Orlov Trotters, pedigree of which contained ancestors of other breeds in various combinations, the inbreeding coefficient Fis had a negative value. The maximum differences between the Fis values were observed between the group of Orlov Trotters pedigree of which did not contain ancestors of other breeds and the group of Orlov Trotters pedigree of which contained ancestors of 3 other breeds: American Standardbred, Russian Trotter and Thoroughbred.