When ancestors transmit their stress: Prenatal maternal stress transmission across generations in a precocial bird

Prenatal maternal stress (PMS) induces life-long effects in offspring. Accumulating evidence suggests that these effects can be transmitted across generations. Although multigenerational effects (F0 mother to F2 grand-offspring) of PMS have been demonstrated in different species, transgenerational transmission (F0 mother to F3 great-grand-offspring) has been less explored. We showed previously in the Japanese quail that PMS increased F1 offspring's emotional reactivity related to epigenetic marks levels in their brain and to modulation of testosterone concentrations in eggs from which they hatched. Here, we evaluated the multi- and transgenerational effects of PMS by analysing the emotional reactivity of the F2 and the F3 offspring. We also investigated the mechanisms potentially involved in the transmission of PMS across generations by analysing the hormonal composition of F1 and F2 eggs and by studying histone post-translational modifications in F3 brains. We showed that PMS increased the neophobia of F2 offspring and F3 females' offspring. We also observed modulations of androgens levels in F1 and F2 eggs but no modifications of the level of histone post-translational modification in F3 brains. Although the mechanisms involved in PMS transmission still need to be explored, our results demonstrate a multi- and transgenerational behavioural effect of PMS in birds.

产前母体应激（Prenatal Maternal Stress，PMS）会对子代产生终生影响。越来越多的研究证据表明，这类效应可跨代传递。尽管已有不同物种中PMS的多代效应（F0母代至F2孙辈）被证实，但跨代传递（F0母代至F3曾孙辈）的相关研究仍较为匮乏。我们此前在日本鹌鹑中发现，PMS会增强F1子代的情绪反应性，该现象与其脑部的表观遗传标记水平以及其孵化所在卵的睾酮浓度调控相关。本研究通过分析F2及F3子代的情绪反应性，评估了PMS的多代与跨代效应。我们还通过检测F1与F2卵的激素组成，并分析F3脑部的组蛋白翻译后修饰，探究了PMS跨代传递的潜在机制。研究结果显示，PMS会提升F2子代以及F3雌性子代的新物恐惧症水平。我们同时观察到F1与F2卵中的雄激素水平存在调控变化，但未发现F3脑部的组蛋白翻译后修饰水平存在改变。尽管PMS传递的具体机制仍有待进一步探究，但本研究结果证实了PMS在鸟类中存在多代与跨代的行为学效应。