MOLECULAR EVIDENCES OF MUTATION-DRIFT EQUILIBRIUM BY MICROSATELLITE MARKERS IN FOUR MEAT PRODUCER BOVINE BREEDS IN BRAZIL

This study aimed to assess possible deviations in mutation -drift equilibrium in bovine breeds. A total of 178 blood samples were collected from Curraleiro Pe-Duro, Tabapua, Guzerat and Senepol breeds for DNA extraction and genotypic analysis by eleven microsatellite markers . The deviation loci number to mutation-drift equilibrium was 1 according to allele infinity model (IAM) and 2 by the stepwise mutation model (SMM) for Curraleiro Pe -Duro breed. For Tabapua breed, there were 5 loci by IAM, and 3 loci by SMM. Although no locus was found by IAM for Guzerat breed, 2 loci were found by SMM. 3 loci by IAM and 2 by SMM were found in Senepol breed. Sign test showed deviation of the number of loci with Heterozygosity excess applying IAM only in Tabapua breed. In Wilcoxon breed sign test showed deviation of the number of loci with h eterozygosity excess in IAM only on Curraleiro Pe-Duro, Tabapua and Senepol breeds. Overall, the results showed presence of mutation -drift equilibrium. No potential bottleneck effect was detected by mode-shift allele distributions, therefore all breeds wer e in normal L-shaped. All breeds have shown evidences of mutation-drift equilibrium due more to high loci number of heterozygosity excess than deficiency of heterozygosity.