Associação de um indel da região reguladora do gene do receptor da melatonina (MTRN1A) com desempenhos leiteiros de búfalas mestiças na região amazônica.

Abstract

Buffalo farming is an important agricultural activity, especially in developing countries and under Amazonian conditions. These animals have good productive and reproductive performance. Animal breeding programs aim to multiply individuals with characteristics, and it is essential to identify economically important molecular markers, which allow the genetic potential of an animal to be determined even before the expression of its phenotype. In this sense, the present study aims to associate an insertion/deletion block (INDEL) in the promoter region of the melatonin receptor 1A gene (MTRN1A) with zootechnical data on milk production in a herd of crossbred buffaloes from the Amazon region. For this purpose, blood samples were collected from 70 crossbred buffaloes from a property located in the municipality of Bujaru, state of Pará. Genomic DNA was extracted using the phenolic method. Then, different primers were selected to perform the polymerase chain reactions (PCR), and their products consisted of 162 bp. Subsequently, these fragments were sequenced, edited and compared with buffalo reference sequences in the NCBI GenBank. The results obtained from the sequencing were tabulated and detailed, determining the allele and genotypic frequencies, observed and expected heterozygosity, inbreeding coefficients (FIS), and the probability of Hardy-Weinberg equilibrium. Comparisons were performed by ANOVA analysis with fixed effect of the genotype and the comparison of means by Tukey test, through the SAS OnDemand program with a significance level of 0.05%. A total of 70 animals were genotyped, and at position -1482 of the MTRN1A regulatory region, the genotypes In/In, In/Del, and Del/Del were observed. The most frequent allele was In (0.64), and the most frequent genotype was In/Del (0.529). The deviations between observed and expected genotypes were not significant (P > 0.05), indicating that the population was in Hardy-Weinberg equilibrium. Comparing the zootechnical data of the average daily production of the buffaloes evaluated in the present study, no significant difference was observed in the association with the different genotypes (P>0.05). Thus, the genotypes evaluated had no effect on milk production in buffaloes raised in the Amazon region. However, Insertion/Deletion polymorphisms can be used in studies of genetic variability, as well as other studies for reproductive characteristics of these animals.