Análisis gwas para resistencia a nematodos gastrointestinales mediante la imputación de genotipos del chip de alta densidad en el ganado ovino

Résumé

The aim of this study was to identify genomic regions influencing the serum levels of Immunoglobulin A (IgA), an indicator trait of resistance to gastrointestinal nematode (GIN) infections in Spanish Churra dairy sheep. With this aim, we performed a Genome-wide Association Study (GWAS) based on imputed genotypes for the Ovine High Density (HD)-chip for a population of 1,686 animals belonging to 16 different half-sib families. The whole population, including the 16 sires and their daughters had available genotypes for the Ovine 50K-chip. The imputation process was based on the 240 animals of the resource population that had been genotyped for the HD-chip. We estimated the accuracy of imputation, using only the genotypes available for the reference population based on a masking strategy designed to avoid any bias in the accuracy estimation. The GWAS identified a significant SNP at the 5% chromosome-wise level, located on OAR15. As complementary approaches, future analyses will exploit the linkage analysis and combined linkage disequilibrium with linkage analysis to exploit the half-sib structure of the studied resource population.