Utilização do índice de fixação alélica para detecção de assinaturas de seleção em bovinos das raças gir, nelore e sindi

Abstract

Selection signatures are regions of the genome that undergo changes in their allele frequencies due to natural or artificial selection, which are associated with certain traits of economic interest. Such regions assists to understand how selection may have altered the genetic constitution of populations. Thus, the objective of this work was to identify and characterize selection signatures present in Gir, Nelore and Sindi animals from Brazil and the Asian continent. After quality control of the samples, 168 Nelore animals from Brazil (NBR), 589 Gir animals from Brazil (GBR), 49 Sindi animals from Brazil (SBR), 49 Nelore animals from India (NIN), 27 Gir animals from India (GIN) and 9 Sindi animals from Pakistan (SPK) were considered in the analyses. Genotypes from the Illumina BovineHD BeadChip high-density panel (777,962 SNPs - single nucleotide polymorphism) was used. The Fst method (allelic fixation index) was used to identify the selection signatures by means of the PLINK v.1.9 software. In defining the signature regions, the 10 largest windows with a size of 50kb were considered. The totals of windows obtained for Fst, in the Gir, Nelore and Sindi breeds were 48,197, 48,484 and 48,820, respectively, and the averages of Fst of the windows were equal to 0.06, 0.03 and 0.04. It was observed that the minimum and maximum values of Fst in the windows ranged from 0.79 to 0.88, for the Gir breed, 0.26 and 0.38, for the Nellore breed, and from 0.48 and 0.61, for the Sindi breed. It was found that the genes DCC, STAG1, DHRS11, ZNF346, MXD3, NSD1, MAP3K3, ALOX5, MBNL1, PIKFYVE, FGFR4 and EXOC2, identified in the regions of selection signatures, were associated, by other studies, with productive, reproductive, and adaptation traits. The selection signatures identified here for Gir, Nelore and Sindi animals indicated which regions characterize the bovine populations from Brazil and which differentiate them from the bovine populations of the Asian continent.