Rezende Fernanda M, Rodriguez Eduardo, Leal-Gutiérrez Joel D, Elzo Mauricio A, Johnson Dwain D, Carr Chad, Mateescu Raluca G
Department of Animal Sciences, University of Florida, Gainesville, FL, United States.
Psychiatry Department, University of California, San Diego, La Jolla, CA, United States.
Front Genet. 2021 Mar 19;12:627055. doi: 10.3389/fgene.2021.627055. eCollection 2021.
Carcass and meat quality are two important attributes for the beef industry because they drive profitability and consumer demand. These traits are of even greater importance in crossbred cattle used in subtropical and tropical regions for their superior adaptability because they tend to underperform compared to their purebred counterparts. Many of these traits are challenging and expensive to measure and unavailable until late in life or after the animal is harvested, hence unrealistic to improve through traditional phenotypic selection, but perfect candidates for genomic selection. Before genomic selection can be implemented in crossbred populations, it is important to explore if pleiotropic effects exist between carcass and meat quality traits. Therefore, the objective of this study was to identify genomic regions with pleiotropic effects on carcass and meat quality traits in a multibreed Angus-Brahman population that included purebred and crossbred animals. Data included phenotypes for 10 carcass and meat quality traits from 2,384 steers, of which 1,038 were genotyped with the GGP Bovine F-250. Single-trait genome-wide association studies were first used to investigate the relevance of direct additive genetic effects on each carcass, sensory and visual meat quality traits. A second analysis for each trait included all other phenotypes as covariates to correct for direct causal effects from identified genomic regions with pure direct effects on the trait under analysis. Five genomic windows on chromosomes BTA5, BTA7, BTA18, and BTA29 explained more than 1% of additive genetic variance of two or more traits. Moreover, three suggestive pleiotropic regions were identified on BTA10 and BTA19. The 317 genes uncovered in pleiotropic regions included anchoring and cytoskeletal proteins, key players in cell growth, muscle development, lipid metabolism and fat deposition, and important factors in muscle proteolysis. A functional analysis of these genes revealed GO terms directly related to carcass quality, meat quality, and tenderness in beef cattle, including calcium-related processes, cell signaling, and modulation of cell-cell adhesion. These results contribute with novel information about the complex genetic architecture and pleiotropic effects of carcass and meat quality traits in crossbred beef cattle.
胴体和肉质是牛肉产业的两个重要属性，因为它们决定了盈利能力和消费者需求。在亚热带和热带地区使用的杂交牛中，这些性状更为重要，因为它们具有卓越的适应性，不过与纯种牛相比，它们往往表现欠佳。其中许多性状测量起来具有挑战性且成本高昂，并且直到牛的生命后期或屠宰后才能获得相关数据，因此通过传统的表型选择来改善这些性状是不现实的，但却是基因组选择的理想候选对象。在杂交群体中实施基因组选择之前，探究胴体和肉质性状之间是否存在多效性效应非常重要。因此，本研究的目的是在一个包含纯种和杂交动物的多品种安格斯 - 婆罗门牛群体中，识别对胴体和肉质性状具有多效性效应的基因组区域。数据包括来自2384头阉牛的10个胴体和肉质性状的表型，其中1038头用GGP牛F - 250进行了基因分型。单性状全基因组关联研究首先用于调查直接加性遗传效应与每个胴体、感官和视觉肉质性状的相关性。对每个性状的第二次分析将所有其他表型作为协变量，以校正来自对所分析性状具有纯直接效应的已识别基因组区域的直接因果效应。在BTA5、BTA7、BTA18和BTA29号染色体上的五个基因组窗口解释了两个或更多性状超过1%的加性遗传方差。此外，在BTA10和BTA19上鉴定出了三个提示性多效性区域。在多效性区域中发现的317个基因包括锚定蛋白和细胞骨架蛋白，它们是细胞生长、肌肉发育、脂质代谢和脂肪沉积的关键参与者，也是肌肉蛋白水解的重要因素。对这些基因的功能分析揭示了与肉牛胴体质量、肉质和嫩度直接相关的基因本体术语，包括钙相关过程、细胞信号传导以及细胞间粘附的调节。这些结果为杂交肉牛胴体和肉质性状的复杂遗传结构和多效性效应提供了新的信息。
