Genome-wide scans to uncover loci underlying bovine reproductive biology

Author(s)

Yuri Tani Utsunomiya

• Document type: Master's Dissertation
• Institution: Universidade Estadual Paulista (Unesp)
• Defense date: 2013-12-16
• Advisor: José Fernando Garcia; Johann Sölkner

Abstract

Reproductive performance has a high impact on the beef cattle industry. The characterization of genomic regions affecting fertility can contribute to the identification of diagnostic markers for reproductive performance and uncover molecular mechanisms underlying complex aspects of bovine reproductive biology. In the first two reported studies, the genomes of progeny-tested Nellore bulls (Bos indicus) were scanned for loci explaining variance in birth weight (BW) and scrotal circunferemce (SC), using data containing over 777,000 single nucleotide polymorphism (SNP) markers. Among the identified loci, a chromosome segment located on autosome 14, encompassing the orthologous human stature gene pleiomorphic adenoma 1 (PLAG1), was found to affect both BW and SC. This locus has been found to have pleiotropic effects on reproduction and body size traits in cattle, and represents a starting point to the dissection of the complex inheritance of bovine fertility. In a separate study, a composite statistical test was developed and applied to scan dairy and beef cattle genomes for evidences of natural and artificial selection signatures. Patterns of genetic variation that may have been shaped by human-driven selection were detected in the genomes of four different cattle breeds (Angus, Brown Swiss, Gyr and Nellore). The study pointed to the Cornichon homolog 3 gene (CNIH3) as a strong candidate involved in the regulation of pre-ovulatory luteinizing hormone surge in Brown Swiss. Although these findings only scratch the surface of the molecular mechanisms underlying bovine reproduction, the loci identified here harbor known and novel functional candidate genes affecting fertility in cattle and offer new insights on complex aspects of bovine reproductive biology (AU)

• FAPESP's process: 11/16643-2 - Genome-wide association study for detection of chromosomal regions related to scrotal circumference in Nellore cattle
• Grantee: Yuri Tani Utsunomiya
• Support Opportunities: Scholarships in Brazil - Master