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Copy number variations and single-nucleotide polymorphisms associated with beef fatty acid profile in nellore cattle

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Author(s):
Marcos Vinícius Antunes de Lemos
Total Authors: 1
Document type: Doctoral Thesis
Press: Jaboticabal. 2017-06-02.
Institution: Universidade Estadual Paulista (Unesp). Faculdade de Ciências Agrárias e Veterinárias. Jaboticabal
Defense date:
Advisor: Fernando Sebastián Baldi Rey
Abstract

The objective of this study was to identify genomic regions of Nellore cattle that present variations in the number of copies (CNV) and to associate these CNV with the fatty acid profile of the meat. In addition, the objective of this study was to carry out a genome-wid association using the single step method (GWASss) to detect genomic regions associated with saturated, mono and polyunsaturated fatty acids, as well as omega 3, 6 and their relationship. The study of the characterization and distribution of CNVs along the Nellore genome was performed by PennCNV software using genotypic data of 3,794 animals, resulting in 399,361 CNVs identified. After quality control, 2,902 were maintained in the analyzes, resulting in 195,873 CNVs, with an average size of 54,744 pb, maximum of 8.7 Mb and minimum 3 kb. The CNV regions were generated by the overlap of the CNVs by CNVRuler software. The chromosomes that showed the highest incidence of CNVR were BTA19 (24.26%), BTA23 (18.68%) and BTA25 (18.05%). Those with the lowest incidence were BTA29 (1.63%), BTA13 (9.72%) and BTA8 (9.72%). The 9,805 CNV regions estimated in the present study covered approximately 13.05% of the bovine genome and overlaped 5,495 genes known to envolve in biological processes that could be involved in the environmental adaptation of the subspecies to tropical areas. The GWASss study showed 115 windows that explained more than 1% of the additive genetic variation for the 22 fatty acids studied. The identification of these regions and their genes, such as ELOVL5, ESRRG, PCYT1A and the ABC group genes (ABCA5, ABCA6 and ABCA10) are genes directly and indirectly related to lipid metabolism. The GWAS between AG phenotypes and CNVs resulted in a total of 186 CNVRs that were significant for the saturated (43), monosaturated (42), polyunsaturated (66) and omegas (35) fatty acids groups, in which 278 genes with described function. These results pointed genes associated to AG of various saturations, and the genes SAMD8 and BSCL2, which are related to lipid metabolism; and the RAPGEF6 gene, related to energetic metabolism. Thus, the numerous genomic regions found in this study, as well as the genes identified in them, should contribute to the formation of a genetic basis of the Nellore beef (Bos indicus) fatty acid profile, contributing to a better selection of the traits associated with improvement of human health. The knowledge of these CNVs could improve the understanding of the genetic and physiological mechanisms that contribute to the productive traits, as well as the selection of more productive and efficient animals. (AU)

FAPESP's process: 13/11853-4 - Analysis of copy number variations in the genome of Nellore and its associations with the fatty acid profile of the meat
Grantee:Marcos Vinícius Antunes de Lemos
Support Opportunities: Scholarships in Brazil - Doctorate