São Paulo State University (UNESP), School of Agricultural and Veterinarian Sciences, Via de Acesso Prof. Paulo Donato Castelane, Jaboticabal, SP, 14884-900, Brazil.
Geneticist Cobb-Vantress, 305 E Main St, Siloam Springs, AR, 72761, USA.
Sci Rep. 2020 Apr 15;10(1):6481. doi: 10.1038/s41598-020-63516-4.
Age at first calving (AFC) plays an important role in the economic efficiency of beef cattle production. This trait can be affected by a combination of genetic and environmental factors, leading to physiological changes in response to heifers' adaptation to a wide range of environments. Genome-wide association studies through the reaction norm model were carried out to identify genomic regions associated with AFC in Nellore heifers, raised under different environmental conditions (EC). The SNP effects for AFC were estimated in three EC levels (Low, Medium, and High, corresponding to average contemporary group effects on yearling body weight equal to 159.40, 228.6 and 297.6 kg, respectively), which unraveled shared and unique genomic regions for AFC in Low, Medium, and High EC levels, that varied according to the genetic correlation between AFC in different EC levels. The significant genomic regions harbored key genes that might play an important biological role in controlling hormone signaling and metabolism. Shared genomic regions among EC levels were identified on BTA 2 and 14, harboring candidate genes associated with energy metabolism (IGFBP2, IGFBP5, SHOX, SMARCAL1, LYN, RPS20, MOS, PLAG1, CHCD7, and SDR16C6). Gene set enrichment analyses identified important biological functions related to growth, hormone levels affecting female fertility, physiological processes involved in female pregnancy, gamete generation, ovulation cycle, and age at puberty. The genomic regions highlighted differences in the physiological processes linked to AFC in different EC levels and metabolic processes that support complex interactions between the gonadotropic axes and sexual precocity in Nellore heifers.
首次产犊年龄（AFC）在肉牛生产的经济效益中起着重要作用。该性状受遗传和环境因素的综合影响，导致小母牛适应广泛环境时发生生理变化。通过反应规范模型进行全基因组关联研究，以鉴定在不同环境条件（EC）下饲养的内罗尔小母牛与 AFC 相关的基因组区域。在三个 EC 水平（低、中、高，分别对应于对 1 岁体重的当代群体效应平均为 159.40、228.6 和 297.6kg）估计了 AFC 的 SNP 效应，这揭示了 AFC 在低、中、高 EC 水平下的共有和独特基因组区域，这些区域根据不同 EC 水平下 AFC 的遗传相关性而有所不同。重要的基因组区域包含了可能在控制激素信号和代谢方面发挥重要生物学作用的关键基因。在 BTA 2 和 14 上鉴定出了 EC 水平之间的共享基因组区域，其中包含与能量代谢相关的候选基因（IGFBP2、IGFBP5、SHOX、SMARCAL1、LYN、RPS20、MOS、PLAG1、CHCD7 和 SDR16C6）。基因集富集分析确定了与生长、影响雌性生育能力的激素水平、女性妊娠、配子生成、排卵周期和青春期年龄相关的重要生物学功能。这些基因组区域突出了不同 EC 水平下与 AFC 相关的生理过程以及支持内罗尔小母牛性腺轴和性早熟之间复杂相互作用的代谢过程的差异。
