Remodeling ancestral phenotypic plasticity in local adaptation: A new framework to explore the role of genetic compensation in the evolution of homeostasis
Remodeling ancestral phenotypic plasticity in local adaptation: A new framework to explore the role of genetic compensation in the evolution of homeostasis
复制标题
重塑局部适应中的祖先表型可塑性：探索遗传补偿在稳态进化中的作用的新框架
DOI：
10.1093/icb/icy117
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发表时间：
2018
影响因子：
2.6
通讯作者：
Cheviron, Zachary A
中科院分区：
文献类型：
--
作者：
Velotta, Jonathan P;Cheviron, Zachary A
表型可塑性并不具有普遍适应性。在某些情况下，可塑性可能导致表型转变，从而降低相对于未诱导状态的适应性。这种适应不良可塑性的一个常见原因是祖先的发育和生理反应系统共同选择来应对新的挑战。由于这些系统的进化是为了应对祖先环境中的特定挑战（例如，局部和短暂的缺氧），因此它们共同选择应对类似但新颖的压力源（例如，高海拔环境氧分压的降低）可能会导致错误的反应，从而降低适应性。在这种情况下，自然选择应该重塑表型可塑性，以抑制这些适应不良反应的表达。由于这些适应不良的反应降低了殖民者在新环境中的适应性，因此祖先可塑性的重塑可能是朝着新的局部最优的适应性行走的最早步骤之一。遗传补偿已被认为是适应性进化的一般形式，它可以抑制适应不良的可塑性，从而在面对新刺激时恢复祖先的特征值。鉴于它们在基本生理功能调节中的核心作用，我们认为遗传补偿通常可以通过修改稳态调节系统来实现。我们进一步建议，可以通过两种机械基础不同的替代策略来实现改变稳态系统的遗传补偿：据我们所知，这些策略尚未得到以前的工作人员的正式认可。然后我们考虑这些替代策略的机制细节如何限制它们的演变。这些考虑使我们认为，遗传补偿最有可能通过补偿性生理变化来进化，这种生理变化保护内部稳态条件，以防止保守反应规范的适应不良部分的表达，而不是可塑性本身的直接进化。最后，我们概述了一个简单的实验框架来检验这一假设。我们的目标是促进研究，旨在更深入地了解表型可塑性是否以及如何在环境变化导致祖先反应适应不良后进行重塑，在当今环境快速变化的时代，这一问题变得越来越重要。
Phenotypic plasticity is not universally adaptive. In certain cases, plasticity can result in phenotypic shifts that reduce fitness relative to the un-induced state. A common cause of such maladaptive plasticity is the co-option of ancestral developmental and physiological response systems to meet novel challenges. Because these systems evolved to meet specific challenges in an ancestral environment (e.g., localized and transient hypoxia), their co-option to meet a similar, but novel, stressor (e.g., reductions in ambient pO2at high elevation) can lead to misdirected responses that reduce fitness. In such cases, natural selection should act to remodel phenotypic plasticity to suppress the expression of these maladaptive responses. Because these maladaptive responses reduce the fitness of colonizers in new environments, this remodeling of ancestral plasticity may be among the earliest steps in adaptive walks toward new local optima. Genetic compensation has been proposed as a general form of adaptive evolution that leads to the suppression of maladaptive plasticity to restore the ancestral trait value in the face of novel stimuli. Given their central role in the regulation of basic physiological functions, we argue that genetic compensation may often be achieved by modifications of homeostatic regulatory systems. We further suggest that genetic compensation to modify homeostatic systems can be achieved by two alternative strategies that differ in their mechanistic underpinnings; to our knowledge, these strategies have not been formally recognized by previous workers. We then consider how the mechanistic details of these alternative strategies may constrain their evolution. These considerations lead us to argue that genetic compensation is most likely to evolve by compensatory physiological changes that safeguard internal homeostatic conditions to prevent the expression of maladaptive portions of conserved reaction norms, rather than direct evolution of plasticity itself. Finally, we outline a simple experimental framework to test this hypothesis. Our goal is to stimulate research aimed at providing a deeper mechanistic understanding of whether and how phenotypic plasticity can be remodeled following environmental shifts that render ancestral responses maladaptive, an issue with increasing importance in our current era of rapid environmental change.