Genome-wide association studies with whole genome sequence for growth traits in Nelore cattle using reaction norm models

Abstract

The genotype environment interaction for beef cattle is routinely investigated by using the reaction norm models in order to predict the breeding values in the different environmental conditions, as well as to assess environmental sensitivity. The inclusion of molecular markers in the estimation of reaction norms allows the identification of candidate genes along the environmental gradients via genome-wide association studies. The aim this project is to perform genome-wide association studies by using sequencing data to map candidate genes for traits in different environmental gradients. About one million phenotypic records of Nellore beef cattle raised in farms located in Brazil and Paraguay will be used. The traits that will be evaluated are birth to weaning weight gain and weaning to yearling weight gain. A total of 151 bulls were sequenced and animals with information from the HD panel had their genotypes imputed for the whole genome sequence totaling more than 10,000 animals with whole genome sequence. The genome-wide association studies will be performed using the single-step GBLUP approache. A network of genes functionally grouped in biological terms will be built in order to investigate evidence of the association of biological processes that are related to sensitivity to environmental variation. (AU)