Neylan Isabelle P, Sih Andrew, Stachowicz John J
Department of Evolution & Ecology, Center for Population Biology UC Davis Davis CA USA.
Bodega Marine Laboratory UC Davis Davis CA USA.
Ecol Evol. 2022 Nov 15;12(11):e9524. doi: 10.1002/ece3.9524. eCollection 2022 Nov.
Transgenerational plasticity (TGP)-when a parent or previous generation's environmental experience affects offspring phenotype without involving a genetic change-can be an important mechanism allowing for rapid adaptation. However, despite increasing numbers of empirical examples of TGP, there appears to be considerable variation in its strength and direction, yet limited understanding of what causes this variation. We compared patterns of TGP in response to stress across two populations with high versus low historical levels of stress exposure. Specifically, we expected that exposure to acute stress in the population experiencing historically high levels of stress would result in adaptive TGP or alternatively fixed tolerance (no parental effect), whereas the population with low levels of historical exposure would result in negative parental carryover effects. Using a common sessile marine invertebrate, , and a split brood design, we exposed parents from both populations to copper or control treatments in the laboratory and then had them brood copper-naïve larvae. We then exposed half of each larval brood to copper and half to control conditions before allowing them to grow to maturity in the field. Maternal copper exposure had a strong negative carryover effect on adult offspring growth and survival in the population without historical exposure, especially when larvae themselves were exposed to copper. We found little to no maternal or offspring treatment effect on adult growth and survival in the population with a history of copper exposure. However, parents from this population produced larger larvae on average and were able to increase the size of their larvae in response to copper exposure, providing a potential mechanism for maintaining fitness and suggesting TGP through maternal provisioning. These results indicate that the ability to adjust offspring phenotype via TGP may be a locally adapted trait and potentially influenced by past patterns of exposure.
跨代可塑性（TGP）——即父母或上一代的环境经历在不涉及基因变化的情况下影响后代表型——可能是实现快速适应的重要机制。然而，尽管TGP的实证例子越来越多，但其强度和方向似乎存在相当大的差异，而对造成这种差异的原因却了解有限。我们比较了两个历史应激暴露水平一高一低的种群对应激的TGP模式。具体而言，我们预计，在历史应激水平较高的种群中，暴露于急性应激会导致适应性TGP或固定耐受性（无亲本效应），而历史暴露水平较低的种群则会产生负面的亲本遗留效应。我们使用一种常见的固着海洋无脊椎动物，并采用分窝设计，在实验室中将两个种群的亲本暴露于铜或对照处理，然后让它们孵化未接触过铜的幼虫。然后，我们将每个幼虫窝的一半暴露于铜环境，另一半暴露于对照环境，之后让它们在野外生长至成熟。在没有历史暴露的种群中，母体铜暴露对成年后代的生长和存活有很强的负面遗留效应，尤其是当幼虫自身也暴露于铜环境时。我们发现，在有铜暴露历史的种群中，母体或后代处理对成年生长和存活几乎没有影响。然而，该种群的亲本平均产生的幼虫更大，并且能够根据铜暴露增加幼虫的大小，这为维持适合度提供了一种潜在机制，并表明通过母体供给存在TGP。这些结果表明，通过TGP调整后代表型的能力可能是一种局部适应性状，并可能受到过去暴露模式的影响。
