Prenatal stress in beef cattle has the potential to result in unexpected, long-term phenotypic changes to an animal's performance. One possible explanation for this phenomenon is stress-induced epigenetic alterations of the genome (e.g., methylation or histone modifications). The objective of this experiment was to identify differential DNA methylation patterns in prenatally stressed (PNS) Brahman females compared to control animals. Pregnant Brahman cows (n = 48) were transported for 2-h periods at 60 ± 5, 80 ± 5, 100 ± 5, 120 ± 5, and 140 ± 5 d. A non-transported group (n = 48) was maintained as a control (Control). Methylation of leukocyte DNA from 28-d old heifer calves born following the PNS exposure (Control n = 8, PNS n = 6) was assessed by reduced representation sodium bisulfite sequencing. Mean methylation ratios at locations across the genome in PNS and Control females were compared using Fisher's Exact t-tests. There were 16,377 CG sites, 309 CHG, and 612 CHH (C= cytosine; G= guanine; H = adenine, cytosine or thymine) sites that were differentially methylated in PNS females compared to the Control (P ≤ 0.05). Differentially methylated regions located in promoters of genes were analyzed to identify genetic pathways and biological functions potentially influenced by the alterations. Important pathways (P ≤ 0.05) included those involved in cell signaling, neurological development, cellular development, immune response, and metabolism. Alterations in expression of genes in pathways such as the “Axonal Guidance Signaling”, “Corticotrophin Releasing Hormone Signaling” and the Neurotrophin/TRK Signaling” pathways could change animal phenotypes.

肉牛的产前压力有可能导致动物表现出意料之外的长期表型变化。这种现象的一种可能解释是基因组的压力诱导表观遗传改变（例如，甲基化或组蛋白修饰）。本实验的目的是鉴定与对照动物相比，在产前紧张（PNS）的婆罗门雌性动物中不同的DNA甲基化模式。将怀孕的婆罗门牛（n  = 48）在60±5、80±5、100±5、120±5和140±5 d下运输2小时。保持非转运组（n  = 48）作为对照（对照组）。PNS暴露后出生的28天龄小母牛犊牛白细胞DNA的甲基化（对照n = 8，PNS n  = 6）通过减少表示的亚硫酸氢钠测序来评估。使用Fisher精确t检验比较了PNS和对照雌性小鼠整个基因组位置的平均甲基化率。有16377个CG位点，309 CHG和612 CHH（C =胞嘧啶; G =鸟嘌呤; H =腺嘌呤，胞嘧啶或胸腺嘧啶），这些差异甲基化在PNS女性相比，控制（位点P ≤0.05）。分析位于基因启动子中的差异甲基化区域，以鉴定可能受到这种改变影响的遗传途径和生物学功能。重要途径（P≤0.05）包括那些参与细胞信号传导，神经系统发育，细胞发育，免疫反应和代谢的物质。诸如“轴突指导信号传导”，“促肾上腺皮质激素释放激素信号传导”和“神经营养蛋白/ TRK信号传导”等途径中基因表达的改变可能会改变动物的表型。