Early-life social experience affects offspring DNA methylation and later life stress phenotype.

Studies in rodents and captive primates suggest that the early-life social environment affects future phenotype, potentially through alterations to DNA methylation. Little is known of these associations in wild animals. In a wild population of spotted hyenas, we test the hypothesis that maternal care during the first year of life and social connectedness during two periods of early development leads to differences in DNA methylation and fecal glucocorticoid metabolites (fGCMs) later in life. Here we report that although maternal care and social connectedness during the den-dependent life stage are not associated with fGCMs, greater social connectedness during the subadult den-independent life stage is associated with lower adult fGCMs. Additionally, more maternal care and social connectedness after den independence correspond with higher global (%CCGG) DNA methylation. We also note differential DNA methylation near 5 genes involved in inflammation, immune response, and aging that may link maternal care with stress phenotype.

针对啮齿类动物与圈养灵长类的研究表明，早期社会环境可通过改变DNA甲基化（DNA methylation）影响个体日后的表型。目前学界对野生动物中这类关联的认知仍较为有限。
本研究以野生斑鬣狗种群为研究对象，验证如下假说：生命第一年的母本抚育与早期发育两个阶段的社会联结，会使个体日后的DNA甲基化水平与粪便糖皮质激素代谢物（fGCMs）出现差异。
本研究结果显示，尽管巢穴依赖生活阶段的母本抚育与社会联结与fGCMs水平无显著关联，但亚成体非巢穴依赖生活阶段的更高社会联结水平，与成年个体更低的fGCMs水平显著相关。此外，巢穴脱离后更多的母本抚育与社会联结，对应更高的全局（%CCGG）DNA甲基化水平。
本研究还发现，5个参与炎症、免疫应答及衰老过程的基因附近存在差异DNA甲基化，这些表观遗传差异或可将母本抚育与应激表型联系起来。