Laskowski Kate L, Seebacher Frank, Habedank Marie, Meka Johannes, Bierbach David
Department of Biology and Ecology of Fishes, Leibniz Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany.
Department of Evolution and Ecology, University of California, Davis, Davis, CA, United States.
Front Physiol. 2021 Oct 12;12:740604. doi: 10.3389/fphys.2021.740604. eCollection 2021.
The capacity to compensate for environmental change determines population persistence and biogeography. In ectothermic organisms, performance at different temperatures can be strongly affected by temperatures experienced during early development. Such developmental plasticity is mediated through epigenetic mechanisms that induce phenotypic changes within the animal's lifetime. However, epigenetic modifiers themselves are encoded by DNA so that developmental plasticity could itself be contingent on genetic diversity. In this study, we test the hypothesis that the capacity for developmental plasticity depends on a species' among-individual genetic diversity. To test this, we exploited a unique species complex that contains both the clonal, genetically identical Amazon molly (), and the sexual, genetically diverse Atlantic molly (). We predicted that the greater among-individual genetic diversity in the Atlantic molly may increase their capacity for developmental plasticity. We raised both clonal and sexual mollies at either warm (28°C) or cool (22°C) temperatures and then measured locomotor capacity (critical sustained swimming performance) and unforced movement in an open field across a temperature gradient that simulated environmental conditions often experienced by these species in the wild. In the clonal Amazon molly, differences in the developmental environment led to a shift in the thermal performance curve of unforced movement patterns, but much less so in maximal locomotor capacity. In contrast, the sexual Atlantic mollies exhibited the opposite pattern: developmental plasticity was present in maximal locomotor capacity, but not in unforced movement. Thus our data show that developmental plasticity in clones and their sexual, genetically more diverse sister species is trait dependent. This points toward mechanistic differences in how genetic diversity mediates plastic responses exhibited in different traits.
补偿环境变化的能力决定了种群的持久性和生物地理学。在变温生物中，早期发育期间经历的温度会强烈影响其在不同温度下的表现。这种发育可塑性是通过表观遗传机制介导的，这些机制在动物的生命周期内诱导表型变化。然而，表观遗传修饰因子本身是由DNA编码的，因此发育可塑性本身可能取决于遗传多样性。在本研究中，我们检验了发育可塑性能力取决于物种个体间遗传多样性的假设。为了验证这一点，我们利用了一个独特的物种复合体，其中既包含克隆的、基因相同的亚马逊帆鳉（），也包含有性繁殖的、基因多样的大西洋帆鳉（）。我们预测，大西洋帆鳉个体间更大的遗传多样性可能会增加它们的发育可塑性能力。我们将克隆的和有性繁殖的帆鳉分别饲养在温暖（28°C）或凉爽（22°C）的温度下，然后测量它们的运动能力（临界持续游泳表现）以及在模拟这些物种在野外经常经历的环境条件的温度梯度下的旷场中的自主运动。在克隆的亚马逊帆鳉中，发育环境的差异导致自主运动模式的热性能曲线发生了变化，但对最大运动能力的影响较小。相比之下，有性繁殖的大西洋帆鳉表现出相反的模式：最大运动能力存在发育可塑性，但自主运动不存在。因此，我们的数据表明，克隆体及其有性繁殖的、遗传上更为多样的姊妹物种的发育可塑性是依赖于性状的。这表明在遗传多样性如何介导不同性状中表现出的可塑性反应方面存在机制差异。
