Evaluación del marcador de resistencia natural Nramp1 en Brahman, Criollo y Holstein

Abstract

Cattle farming is considered one of the main sources of economic income in Ecuador. For this reason, many producers have focused on productive improvement through genetic crosses with foreign breeds, which has caused the decrease of the endemic Criollo cattle population, and the loss of its adaptability properties associated with resistance to bacterial diseases of importance in our country. The Nramp1 gene has characteristics considered determinants in the presence of an infection by various intracellular pathogens. For this reason, scientists have based their research on determining whether the polymorphism of this gene can explain the racial variation in susceptibility to different diseases. This research evaluated the existence of a polymorphism in the coding sequence of the Nramp1 gene among cattle of the Holstein, Brahman and Criolla breeds. For this purpose, 30 total DNA samples from each of the mentioned breeds were used. Genotyping was carried out by PCR and SSCA for the detection of polymorphisms of the SPN4 and SPN5 loci of Nramp1. The alleles found for SNP4 express a single homozygous fixed allele (A) in all homozygous individuals, and for SNP5 the Holstein breed reveals a homozygous fixed allele (A), while in Brahman and Criollo cattle, a high predominance of heterozygosity (AB) was found. In conclusion, it was shown that there is variation in the alleles that encode the Nramp1 protein between breeds, however, the existence of a polymorphism was not proven