Doyle Jennifer L, Berry Donagh P, Veerkamp Roel F, Carthy Tara R, Walsh Siobhan W, Evans Ross D, Purfield Deirdre C
Animal and Grassland Research and Innovation Centre, Moorepark, Teagasc, Fermoy, Ireland.
Department of Science, Waterford Institute of Technology, Waterford, Ireland.
Front Genet. 2020 Feb 4;11:20. doi: 10.3389/fgene.2020.00020. eCollection 2020.
Linear type traits describing the skeletal characteristics of an animal are moderately to strongly genetically correlated with a range of other performance traits in cattle including feed intake, reproduction traits and carcass merit; thus, type traits could also provide useful insights into the morphological differences among animals underpinning phenotypic differences in these complex traits. The objective of the present study was to identify genomic regions associated with five subjectively scored skeletal linear traits, to determine if these associated regions are common in multiple beef and dairy breeds, and also to determine if these regions overlap with those proposed elsewhere to be associated with correlated performance traits. Analyses were carried out using linear mixed models on imputed whole genome sequence data separately in 1,444 Angus, 1,129 Hereford, 6,433 Charolais, 8,745 Limousin, 1,698 Simmental, and 4,494 Holstein-Friesian cattle, all scored for the linear type traits. There was, on average, 18 months difference in age at assessment of the beef versus the dairy animals. While the majority of the identified quantitative trait loci (QTL), and thus genes, were both trait-specific and breed-specific, a large-effect pleiotropic QTL on BTA6 containing the and genes was associated with all skeletal traits in the Limousin population and with wither height in the Angus. Other than that, little overlap existed in detected QTLs for the skeletal type traits in the other breeds. Only two QTLs overlapped the beef and dairy breeds; both QTLs were located on BTA5 and were associated with height in both the Angus and the Holstein-Friesian, despite the difference in age at assessment. Several detected QTLs in the present study overlapped with QTLs documented elsewhere that are associated with carcass traits, feed intake, and calving difficulty. While most breeding programs select for the macro-traits like carcass weight, carcass conformation, and feed intake, the higher degree of granularity with selection on the individual linear type traits in a multi-trait index underpinning the macro-level goal traits, presents an opportunity to help resolve genetic antagonisms among morphological traits in the pursuit of the animal with optimum performance metrics.
描述动物骨骼特征的线性类型性状与牛的一系列其他生产性能性状存在中度到高度的遗传相关性，这些性状包括采食量、繁殖性状和胴体品质；因此，类型性状也可以为动物之间的形态差异提供有用的见解，这些差异是这些复杂性状表型差异的基础。本研究的目的是确定与五个主观评分的骨骼线性性状相关的基因组区域，确定这些相关区域在多个肉牛和奶牛品种中是否常见，并确定这些区域是否与其他地方提出的与相关生产性能性状相关的区域重叠。使用线性混合模型对推算的全基因组序列数据进行分析，分别在1444头安格斯牛、1129头海福特牛、6433头夏洛莱牛、8745头利木赞牛、1698头西门塔尔牛和4494头荷斯坦-弗里生牛中进行，所有牛都对线性类型性状进行了评分。肉牛和奶牛在评估时的年龄平均相差18个月。虽然大多数已鉴定的数量性状位点（QTL）以及相应的基因都是性状特异性和品种特异性的，但位于BTA6上包含 和 基因的一个大效应多效性QTL与利木赞牛群体中的所有骨骼性状以及安格斯牛的鬐甲高度相关。除此之外，其他品种中检测到的骨骼类型性状的QTL几乎没有重叠。只有两个QTL在肉牛和奶牛品种中重叠；这两个QTL都位于BTA5上，并且与安格斯牛和荷斯坦-弗里生牛的身高相关，尽管评估时的年龄存在差异。本研究中检测到的几个QTL与其他地方记录的与胴体性状、采食量和产犊难度相关的QTL重叠。虽然大多数育种计划选择胴体重、胴体形态和采食量等宏观性状，但在支持宏观目标性状的多性状指数中对个体线性类型性状进行更精细的选择，为在追求具有最佳性能指标的动物时帮助解决形态性状之间的遗传拮抗提供了机会。
