Associação do gene da leptina com características produtivas em bovinos da raça Nelore

Abstract

With the advent of molecular biology techniques, it became possible to do more detailed study of genes involved in certain phenotypes of quantitative traits, which made progress in animal breeding programs through the use of marker-assisted selection. The aim of this study was to associate the genotypes of the polymorphisms found in exon 2 of the leptin gene with production traits in Nelore cattle. The biological material for the study was collected from 100 male Nelore and it was done the extraction of DNA followed by RFLP-PCR reactions with the enzymes ClaI and Kpn2I. The genetic analysis was performed with the aid of CERVUS 3.0 software and statistical analysis with the computer package SAS 9.2. Among the animals analyzed with the enzyme ClaI, 80 were heterozygous (A / T) and 20 homozygous (A / A). The gene frequency of allele A was 0.60 and the T allele was 0.40. The genotype frequencies were AA = 0.20 and AT = 0.80. The PIC was 0.36. The observed heterozygosity was 0.80 and the expected 0.48. For the enzime Kpn2I, 38 were heterozygous (C / T) and 63 homozygous (C / C). The gene frequency of allele C was 0.81 and the T allele was 12:19. The genotypic frequencies were CC = 0.62 and CT = 0.38. The PIC was 0.26. The observed heterozygosity was 0.38 and the expected 0.31. It was not found homozygous genotype (T / T) for any of the markers and in both cases the population was not in Hardy-Weinberg equilibrium (P> 0.05). Significant associations were found between the polymorphisms in exon 2 of the leptin gene with the production traits of Nelore cattle.