Data from: Paternal care, epigenetics and fitness enhancing effects on offspring anxiety

In many animals, including humans, interactions with caring parents can have long-lasting effects on offspring sensitivity to stressors. However, whether these parental effects impact offspring fitness in nature is often unclear. In addition, despite evidence that maternal care can influence offspring behaviour via epigenetic alterations to the genome, it remains unclear whether father care has similar effects. Here we show in threespined stickleback fish with father-only care, that the direct care provided by fathers, like that of mammalian mothers, affects offspring anxiety and the potential for epigenetic alterations to the offspring genome. We find that families are differentially vulnerable to early stress and fathers can compensate for this differential sensitivity with the quality of their care. This variation in paternal care is also linked to expression in offspring brains of a DNA methyltransferase (Dnmt3a) responsible for de novo methylation. Importantly for the evolution of paternal care, we show that these paternal effects are potentially adaptive and anxious offspring are unlikely to survive an encounter with a predator. By supplying offspring care, fathers reduce offspring anxiety thereby increasing the survival of their offspring – not in the traditional sense through resource provisioning but through an epigenetic effect on offspring behavioural development.

包括人类在内的诸多动物，其与抚育双亲的互动会对子代的应激敏感性产生持久影响。然而，这类亲本效应是否会在自然环境中对子代的适合度造成影响，目前仍尚不明确。此外，尽管已有研究证实母本抚育可通过基因组的表观遗传修饰（epigenetic alterations）影响子代行为，但父本抚育是否能产生类似效应，目前仍未有定论。本研究以仅实行父本抚育的三刺棘鱼（threespined stickleback fish）为研究对象，结果显示：父本提供的直接抚育行为，与哺乳动物母本的抚育行为类似，会对子代的焦虑状态以及子代基因组发生表观遗传修饰的潜力产生影响。研究发现，不同家族对早期应激的易感性存在显著差异，而父本可通过提升抚育质量来弥补这种敏感性差异。这种父本抚育行为的个体差异，还与子代大脑中负责从头甲基化（de novo methylation）的DNA甲基转移酶（DNA methyltransferase，Dnmt3a）的表达水平密切相关。值得关注的是，从父本抚育的演化视角来看，本研究证实这类父本效应具备潜在适应性：遭遇捕食者时，焦虑型子代的存活率极低。父本通过为子代提供抚育，能够降低子代的焦虑水平，进而提升子代的存活率——这并非通过传统的资源供给途径实现，而是通过对子代行为发育产生表观遗传调控效应达成的。