Pausch Hubert, Mapel Xena Marie
Animal Genomics, Department of Environmental Systems Science, ETH Zurich, Universitaetstrasse 2, 8092 Zurich, Switzerland.
Animal Genomics, Department of Environmental Systems Science, ETH Zurich, Universitaetstrasse 2, 8092 Zurich, Switzerland.
Animal. 2023 May;17 Suppl 1:100742. doi: 10.1016/j.animal.2023.100742.
Cattle are a well-suited "model organism" to study the genetic underpinnings of variation in male reproductive performance. The adoption of artificial insemination and genomic prediction in many cattle breeds provide access to microarray-derived genotypes and repeated measurements for semen quality and insemination success in several thousand bulls. Similar-sized mapping cohorts with phenotypes for male fertility are not available for most other species precluding powerful association testing. The repeated measurements of the artificial insemination bulls' semen quality enable the differentiation between transient and biologically relevant trait fluctuations, and thus, are an ideal source of phenotypes for variance components estimation and genome-wide association testing. Genome-wide case-control association testing involving bulls with either aberrant sperm quality or low insemination success revealed several causal recessive loss-of-function alleles underpinning monogenic reproductive disorders. These variants are routinely monitored with customised genotyping arrays in the male selection candidates to avoid the use of subfertile or infertile bulls for artificial insemination and natural service. Genome-wide association studies with quantitative measurements of semen quality and insemination success revealed quantitative trait loci for male fertility, but the underlying causal variants remain largely unknown. Moreover, these loci explain only a small part of the heritability of male fertility. Integrating genome-wide association studies with gene expression and other omics data from male reproductive tissues is required for the fine-mapping of candidate causal variants underlying variation in male reproductive performance in cattle.
牛是研究雄性繁殖性能变异遗传基础的理想“模式生物”。许多牛品种采用人工授精和基因组预测，可获取微阵列衍生的基因型，并对数千头公牛的精液质量和授精成功率进行重复测量。对于大多数其他物种而言，无法获得类似规模且具有雄性生育力表型的定位群体，这使得强大的关联测试无法进行。人工授精公牛精液质量的重复测量能够区分短暂的和生物学上相关的性状波动，因此，是估计方差成分和全基因组关联测试的理想表型来源。涉及精子质量异常或授精成功率低的公牛的全基因组病例对照关联测试揭示了几种导致单基因生殖障碍的因果隐性功能丧失等位基因。在雄性候选选择中，通过定制基因分型阵列对这些变异进行常规监测，以避免使用生育力低下或不育的公牛进行人工授精和自然配种。对精液质量和授精成功率进行定量测量的全基因组关联研究揭示了雄性生育力的数量性状位点，但其潜在的因果变异在很大程度上仍然未知。此外，这些位点仅解释了雄性生育力遗传力的一小部分。需要将全基因组关联研究与来自雄性生殖组织的基因表达和其他组学数据相结合，以精细定位牛雄性繁殖性能变异潜在的候选因果变异。
