Department of Animal, Veterinary & Food Sciences, University of Idaho, Moscow, ID 83843, USA.
Department of Animal Sciences, Washington State University, Pullman, WA 99164, USA.
Genes (Basel). 2021 Feb 2;12(2):217. doi: 10.3390/genes12020217.
The ability of livestock to reproduce efficiently is critical to the sustainability of animal agriculture. Antral follicle count (AFC) and reproductive tract scores (RTS) can be used to estimate fertility in beef heifers, but the genetic mechanisms influencing variation in these measures are not well understood. Two genome-wide association studies (GWAS) were conducted to identify the significant loci associated with these traits. In total, 293 crossbred beef heifers were genotyped on the Bovine GGP 50K chip and genotypes were imputed to 836,121 markers. A GWAS was performed with the AFC phenotype for 217 heifers with a multi-locus mixed model, conducted using the year, age at time of sampling and principal component analysis groupings as the covariates. The RTS GWAS was performed with 289 heifers using an additive correlation/trend test comparing prepubertal to pubertal heifers. The loci on chromosomes 2, 3 and 23 were significant in the AFC GWAS and the loci on chromosomes 2, 8, 10 and 11 were significant in the RTS GWAS. The significant region on chromosome 2 was similar between both analyses. These regions contained genes associated with cell proliferation, transcription, apoptosis and development. This study proposes candidate genes for beef cattle fertility, although future research is needed to elucidate the precise mechanisms.
家畜高效繁殖的能力对动物农业的可持续性至关重要。卵巢腔卵泡计数（AFC）和生殖道评分（RTS）可用于估计肉牛小母牛的繁殖力，但影响这些指标变化的遗传机制尚不清楚。进行了两项全基因组关联研究（GWAS），以确定与这些性状相关的重要基因座。共有 293 头杂交肉牛小母牛在 Bovine GGP 50K 芯片上进行了基因分型，并将基因型推断为 836,121 个标记。使用多基因混合模型对 217 头小母牛的 AFC 表型进行了 GWAS，使用年份、采样时的年龄和主成分分析分组作为协变量进行了分析。使用加性相关/趋势检验对 289 头小母牛进行了 RTS GWAS，比较了青春期前和青春期的小母牛。在 AFC GWAS 中，第 2、3 和 23 号染色体上的基因座是显著的，而在 RTS GWAS 中，第 2、8、10 和 11 号染色体上的基因座是显著的。这两个分析中在第 2 号染色体上的显著区域是相似的。这些区域包含与细胞增殖、转录、凋亡和发育相关的基因。本研究提出了肉牛生育力的候选基因，但需要进一步研究来阐明确切的机制。
