Mapping and characterization of eQTL associated with meat fatty acids in Nelore cattle

• Grant number: 16/21201-2
• Support type: Scholarships in Brazil - Post-Doctorate
• Effective date (Start): April 01, 2017
• Effective date (End): March 31, 2019
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Genetics and Improvement of Domestic Animals
• Principal researcher: Henrique Nunes de Oliveira
• Grantee: Camila Urbano Braz
• Home Institution: Faculdade de Ciências Agrárias e Veterinárias (FCAV). Universidade Estadual Paulista (UNESP). Campus de Jaboticabal. Jaboticabal , SP, Brazil
• Associated research grant: 09/16118-5 - Genomic tools to genetic improvement of direct economic important traits in Nelore cattle, AP.TEM
• Associated scholarship(s): 17/21757-3 - Exploring eQTL analysis for beef fatty acid profile in Nelore cattle, BE.EP.PD

Abstract

The Brazilian herd consists mainly of Nelore cattle, which is known for its adaptability in tropical climates. However, the meat produced by Bos indicus is characterized by low intramuscular and subcutaneous fat content, which influences negatively on the meat quality. On the other hand, the meat of Bos indicus has presented significant desirable concentrations of fatty acids for human health. Health professionals have recommended reducing consumption of saturated fatty acids and increased intake of unsaturated fatty acids. This has motivated the development of research aimed at better understanding the biological and functional mechanisms involved in the genes regulation and expression responsible for fatty acids synthesis. RNA-Seq technology allows detection of all expressed genes, enabling the mapping of the expression Quantitative Trait Loci (eQTLs). Moreover, the mapping may contribute to dissect the genetic architecture of variation in gene expression and their effects on the phenotype. The aim of this project is to map and characterize the eQTLs existing in the transcriptome of Nelore cattle for fatty acid profile, searching to understand how the regulatory variants influence on the phenotypic variability of the trait. Phenotypic and gene expression information of Nellore bulls, participants of Nellore Qualitas breeding program, will be used. For statistical analysis, 20 different fatty acids as well as the sum of saturated, monounsaturated, polyunsaturated, omega 6 and omega 3 fatty acids and the polyunsaturated/saturated and omega-6/omega 3 ratios, will be used. The search for eQTLs will be performed using the TReCASE method, which will also be possible to identify the eQTLs acting in cis or in trans. The identification of eQTL hotspots will be conducted by permutation test, which permute the genotypes among the samples, but preserves the correlation structure in the gene expression data. In addition, the regions of eQTL detected will be compared with results from genome-wide association studies previously conducted to the fatty acid profile and correlated traits. It expected that this study reveal the mechanisms of gene regulation for fatty acids, leading a better biological understanding of the phenotypic variability of the trait and thus, contribute to the scientific community through understanding the architecture of genes regulation for the trait studied. (AU)