DNA methylation biomarkers of fertility in bulls

奶牛的繁殖力已经成为一个真正令人担忧的问题，尽管在基因选择方面取得了进展，以缓解这一表型。轻度不孕症患病率增加的一个可能解释是，除了遗传编程外，表观遗传编程也会起作用。表观遗传效应的分子基础是DNA甲基化的稳定性，DNA甲基化通过复制从细胞传递到细胞。事实上，我们是世界上少数几个在牛DNA甲基化分析方面拥有丰富专业知识的研究小组之一，该分析可用于研究基因与环境的相互作用及其对下一代的潜在影响。现在在啮齿动物、绵羊和奶牛身上很好地证明了这种现象可能会影响下一代的生育能力。在哺乳动物身上也很好地证明了雄性环境可以影响后代的表型。因此，假设新陈代谢应激的雌性公牛可以在其睾丸中产生具有特定表观基因组的公牛，从而直接影响精子，损害生育能力，或者影响胚胎，导致女儿的表型改变。为了筛选出这样的缩影，重要的是比较相对较多的公牛数量，但去掉与个体相关的个体变异。为了实现这一任务，我们将分析100头公牛的精子样本，根据公牛的生育能力和女儿的生育能力这两种表型来确定与表型相关的代际生物标志物。公牛将使用一种新的DNA捕获方法进行对比，然后根据表型进行测序，以确定DNA甲基化的变化。然后将使用焦磷酸测序来验证与生育相关的特定生物标记物。然后将对这些标记进行测试。用血液和头发而不是水泥来测试出生时的诊断潜力。

Fertility in dairy cows has become a real concern despite the progression made in genetic selection to alleviate this phenotype. One of the possible explanations for the increased prevalence of mild infertility could be the epigenetic programming that would act in addition to genetic programming. The molecular basis for epigenetic effect is the stability of DNA methylation which is transmitted from cells to cells through replication. We are actually one of the few research groups in the world with extensive expertise in bovine DNA methylation analysis which could be used to study gene-environment interaction and the potential impact on the next generation. It is now well demonstrated in rodents, sheep and cows that the phenomena may impact the next generation fertility. It is also well demonstrated in mammals that the male environment can influence the phenotype of the offspring. Therefore, the hypothesis is that metabolically stressed females could generate bulls with a particular epigenome in their testis resulting in either a direct effect on the sperm impairing fertility or affected embryos resulting in a modified phenotype in the daughter. To screen for such epitome, it would be important to compare a relatively high number of bulls but removing the individual variations associated with individuals. To achieve such a task, we will analyze sperm samples from 100 bulls according to 2 phenotypes, bull's fertility and daughter's fertility which could identify intergenerational biomarkers associated with the phenotype. Bulls will be contrasted using a new DNA capture approach followed by sequencing to identify DNA methylation changes according to phenotypes. Then pyrosequencing will be used to validate specific biomarkers associated with fertility. These markers will then be tested. on blood and hair instead of cement to test a diagnostic potential at birth.