Zhang Ying, Bruna de Lima Camila, Labrecque Rémi, Sirard Marc-André
Centre de recherche en reproduction, développement et santé intergénérationnelle (CRDSI), Département des Sciences Animales, Faculté des sciences de l'agriculture et de l'alimentation, Université Laval, Québec, Canada.
SEMEX Boviteq, 3450 Rue Sicotte, Saint-Hyacinthe, QC, Canada.
Reproduction. 2023 Mar 31;165(5):557-568. doi: 10.1530/REP-22-0283. Print 2023 May 1.
Bull fertility is an important economic trait, this study identified some DNA methylation biomarkers that are associated with bull fertility.
Subfertile bulls may cause huge economic losses in dairy production since their semen could be used to inseminate thousands of cows by artificial insemination. This study adopted whole-genome enzymatic methyl sequencing and aimed to identify candidate DNA methylation markers in bovine sperm that correlate with bull fertility. Twelve bulls were selected (high bull fertility = 6; low bull fertility = 6) based on the industry's internally used Bull Fertility Index. After sequencing, a total of 450 CpG had a DNA methylation difference higher than 20% (q < 0.01) had been screened. The 16 most significant differentially methylated regions (DMRs) were identified using a 10% methylation difference cut-off (q < 5.88 × 10-16). Interestingly, most of the differentially methylated cytosines (DMCs) and DMRs were distributed on the X and Y chromosomes, demonstrating that the sex chromosomes play essential roles in bull fertility. Additionally, the functional classification showed that the beta-defensin family, zinc finger protein family, and olfactory and taste receptors could be clustered. Moreover, the enriched G protein-coupled receptors such as neurotransmitter receptors, taste receptors, olfactory receptors, and ion channels indicated that the acrosome reaction and capacitation processes are pivotal for bull fertility. In conclusion, this study identified the sperm-derived bull fertility-associated DMRs and DMCs at the whole genome level, which could complement and integrate into the existing genetic evaluation methods, increasing our decisive capacity to select good bulls and explain bull fertility better in the future.
公牛生育力是一项重要的经济性状，本研究鉴定了一些与公牛生育力相关的DNA甲基化生物标志物。
不育公牛可能会给奶牛生产造成巨大经济损失，因为它们的精液可通过人工授精使数千头母牛受孕。本研究采用全基因组酶促甲基化测序，旨在鉴定牛精子中与公牛生育力相关的候选DNA甲基化标记。根据行业内部使用的公牛生育力指数，选择了12头公牛（高生育力公牛 = 6头；低生育力公牛 = 6头）。测序后，共筛选出450个DNA甲基化差异高于20%（q < 0.01）的CpG。使用10%的甲基化差异阈值（q < 5.88 × 10-16）鉴定出16个最显著的差异甲基化区域（DMR）。有趣的是，大多数差异甲基化胞嘧啶（DMC）和DMR分布在X和Y染色体上，表明性染色体在公牛生育力中起着至关重要的作用。此外，功能分类显示β-防御素家族、锌指蛋白家族以及嗅觉和味觉受体可聚类。而且，富集的G蛋白偶联受体，如神经递质受体、味觉受体、嗅觉受体和离子通道，表明顶体反应和获能过程对公牛生育力至关重要。总之，本研究在全基因组水平上鉴定了源自精子的与公牛生育力相关的DMR和DMC，这可以补充并整合到现有的遗传评估方法中，提高我们未来挑选优质公牛的决策能力，并更好地解释公牛生育力。
