Dissecting Traits in Bos indicus Influenced Cattle By Combining ‘Omics Approaches

The McGregor Genomics herd is comprised of families of Nellore-Angus cross cattle that were produced to identify and characterize QTL for production efficiency, animal health and wellbeing, and carcass quality.  More than 100 phenotypic measurements were collected per animal, and DNA and tissue samples have been archived.  In the first cycle of this project, we produced Nellore-Angus F₂ cattle by embryo transfer.  In the second cycle, all four reciprocal crosses of Nellore-Angus F₂ cattle were produced by natural service.  The third and fourth cycles of this project are F₃ and F₄ Nellore-Angus crosses, respectively. Initially, we genotyped the first cycle (n = 776) with the BovSNP50 assay and performed QTL analyses.  Later, we sequenced to 30x coverage the Nellore bulls (n = 7) and Angus cows (n = 6) that were founders of the first cycle. Discovered SNP were used to impute the whole population to sequence scale.  Parent-of-origin and breed-of-origin of imputed haplotypes also were assigned. We have combined these data with expression (mRNA and microRNA) and/or protein data to characterize QTL.  We will share our progress in characterizing QTL for traits with different underlying architectures.