The reproductive performance of bulls has a major impact on the beef industry, affecting generation intervals, the rate of genetic change, and the amount of product that can be sent to the market. Scrotal circumference evaluated at yearling (SC) is the most recorded reproductive trait in beef cattle, and is used as a major selection criterion to improve precocity and fertility. The characterization of genomic regions affecting SC can contribute to the identification of diagnostic markers of reproductive performance and unravel molecular mechanisms involved in bovine reproductive biology. Recently, the candidate performed a genome-wide mapping of chromosome segments explaining differences in SC in 861 Nellore bulls (Bos indicus), using data from over 777,000 single nucleotide polymorphism (SNP) markers. Loci that excel from the genome background were identified on chromosomes 4, 6, 7, 10, 14, 18 and 21. The majority of these regions were previously found to be associated with reproductive and body size traits in cattle. The signal on chromosome 14 replicates the pleiotropic quantitative trait locus encompassing PLAG1 that affects male fertility in cattle and stature in several species, including humans. New candidate genes have been proposed for SC from this study, which affect growth and testicular size in other animal models. This project aims at the refinement of these loci using next-generation sequencing (next generation sequencing - NGS) data, aiming at investigating the putative causality of SNPs, copy number variants, insertions and deletions found in these regions.
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