Light-induced stress as a primary evolutionary driver of eye origins
Light-induced stress as a primary evolutionary driver of eye origins
复制标题
光诱导的压力是眼睛起源的主要进化驱动力
DOI：
10.1093/icb/icz064
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发表时间：
2019
影响因子：
2.6
通讯作者：
Oakley, Todd H.
中科院分区：
文献类型：
--
作者：
Swafford, Andrew J. M.;Oakley, Todd H.
眼睛是典型的复杂特征，我们对眼睛进化的理解指导着一般的特征进化模型。长期以来，对眼睛进化的一种描述认为，自然选择有利于形态变化，从而增加感知光线的功能。虽然这在一定程度上是正确的，但这种对视觉表现的关注并不能完全解释为什么即使在眼睛进化之后，漫反射光敏性仍然存在，或者为什么眼睛进化了很多次，每次都使用类似的构建块。在这里，我们简要回顾大量文献，指出眼睛的大多数遗传成分历史上对光直接引起的应激做出反应，包括DNA的紫外线损伤、氧化应激和醛的产生。我们认为，在眼睛自身进化之前和过程中，光诱导应激通过聚集修复和防止光应激损伤的基因，在眼睛的进化中发挥了直接和突出的作用。压力修复和压力预防基因最初可能是作为对光的可塑性反应和/或作为有益的突变来部署的，在光突出的地方，基因驱动表达。这些应激反应基因感知、屏蔽和折射光，但仅作为对持续的光压力的反应。一旦在调控基因控制下，它们可以在光胁迫出现之前表达，作为一个模块进化，并受到自然选择的影响，以增加感光功能，最终导致复杂的眼睛和行为。认识到压力在眼睛进化中潜在的突出作用，引发了关于可塑性和同化的讨论，并为为什么相似的基因在收敛的眼睛中重复使用提供了一个假说。扩大眼睛进化的驱动力，通常会鼓励人们考虑复杂的新颖性和创新性的可塑性/同化和突变/选择的多方面机制。
Eyes are quintessential complex traits and our understanding of their evolution guides models of trait evolution in general. A long-standing account of eye evolution argues natural selection favors morphological variations that allow increased functionality for sensing light. While certainly true in part, this focus on visual performance does not entirely explain why diffuse photosensitivity persists even after eyes evolve, or why eyes evolved many times, each time using similar building blocks. Here, we briefly review a vast literature indicating most genetic components of eyes historically responded to stress caused directly by light, including ultraviolet damage of DNA, oxidative stress, and production of aldehydes. We propose light-induced stress had a direct and prominent role in the evolution of eyes by bringing together genes to repair and prevent damage from light-stress, both before and during the evolution of eyes themselves. Stress-repair and stress-prevention genes were perhaps originally deployed as plastic responses to light and/or as beneficial mutations genetically driving expression where light was prominent. These stress-response genes sense, shield, and refract light but only as reactions to ongoing light stress. Once under regulatory-genetic control, they could be expressed before light stress appeared, evolve as a module, and be influenced by natural selection to increase functionality for sensing light, ultimately leading to complex eyes and behaviors. Recognizing the potentially prominent role of stress in eye evolution invites discussions of plasticity and assimilation and provides a hypothesis for why similar genes are repeatedly used in convergent eyes. Broadening the drivers of eye evolution encourages consideration of multi-faceted mechanisms of plasticity/assimilation and mutation/selection for complex novelties and innovations in general.