Genome-wide association study for intramuscular fat deposition and composition in Nellore cattle

Authors: CESAR, ALINE SM - Universidad De Sao Paulo; REGITANO, LUCIANA CA - Embrapa National Research Center; TULLIO, RYMER - Embrapa National Research Center; LANNAL, DANTE PD - Universidad De Sao Paulo; NASSU, RENATA - Embrapa National Research Center; MUDADO, MAURICIO - Embrapa National Research Center; OLIVEIRA, PRISCILA SN - Universidade Federal De Sao Carlos; NASCIMENTO, MICHELE L DO - Universidad De Sao Paulo; CHAVES, AMALIA - Universidad De Sao Paulo; ALENCAR, MAURICIO - Embrapa National Research Center; Sonstegard, Tad; GARRICK, DORIAN - Iowa State University; REECY, JAMES - Iowa State University; COUTINHO, LUIZ - Universidad De Sao Paulo

Submitted to: BioMed Central (BMC) Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/28/2014
Publication Date: 3/25/2014
Citation: Cesar, A., Regitano, L., Tullio, R.R., Lannal, D., Nassu, R.T., Mudado, M.A., Oliveira, P., Nascimento, M., Chaves, A., Alencar, M.M., Sonstegard, T.S., Garrick, D., Reecy, J.M., Coutinho, L.L. 2014. Genome-wide association study for intramuscular fat deposition and composition in Nellore cattle. BioMed Central (BMC) Genetics. 15(1):39.

Interpretive Summary: It is possible to analyze high-density DNA marker (single nucleotide polymorphism or SNP-based data) to find regions of the cattle genome that have rapidly changed due to artificial selection for genetic improvement of meat quality traits. This study uses high-density, genome-wide SNP data (700,000 markers) to identify regions of the genome affecting intramuscular fat deposition (marbling) in the Nelore breed of Bos indicus cattle from Brazil. This tropically adapted breed is known for producing meat usually with less marbling relative to breeds of U.S. cattle. The results provide the first evidence as to what regions of the genome are important for marbling in Nelore cattle, and most of these regions do not overlap with previous studies in continental breeds of cattle. Studies with other populations from the Nelore breed will be required to validate the results of this study. This information can be used to inform further investigations to improve meat quality in tropically adapted cattle.

Technical Abstract: Red meat from Bos taurus and Bos indicus breeds are an important source of nutrients for humans and intramuscular fat (IMF) influences its flavor, nutritional value and impacts human health. Human consumption of fat that contains high levels of monounsaturated fatty acids (MUFA) can reduce the concentration of undesirable cholesterol (LDL) in circulating blood. Different feeding practices and genetic variation within and between breeds influences the amount of IMF and fatty acid composition in meat. However, difficulty and costs associated with determining fatty acid composition limits beef cattle breeding programs for a healthier fatty acid profile. Selection of animals with adequate amounts of IMF and improved fatty acid composition (FA) is hindered by difficulties in measuring these traits. In this study, we employed a high-density SNP chip and a Bayesian approach to identify genomic regions that control IMF and fatty acid composition in Nelore cattle, a Bos indicus breed. Twenty-five genomic regions associated with intramuscular fat deposition and composition (1-Mb SNP window) that explain = 1% of the genetic variance were identified on chromosomes 2, 3, 6, 7, 8, 9, 10, 11, 12, 17, 26 and 27. Many of the regions identified were not previously detected in other breeds. The genes present in these regions were also identified and can help explain the genetic basis of deposition and composition of fat in cattle. The genomic regions and genes identified contribute to a better understanding of the genetic control of fatty acid deposition and can lead to DNA-based selection strategies to improve meat quality for human consumption.