Functional circadian clocks are essential for fitness in diverse ecosystems, facilitating detection of predictable light-dark and temperature cycles. The molecular basis of endogenous clocks is variable across the tree of life, but it has one omnipresent attribute: natural genetic diversity that manifests as variation for instance in circadian period length around the hypothesised optimum of 24 hours. Latitudinal variation in photoperiod alone is unlikely to account for the vast diversity documented in varied organisms, but we have yet to achieve a solid understanding of the interplay between clock variability and natural selection. Recent circadian studies sampling populations have drawn attention to the hierarchical structure of genetic diversity in the wild, unveiling pronounced genetic variation even on a scale of metres.

中文翻译：

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昼夜节律调节中遗传变异的适应性益处。

功能性生物钟对于适应各种生态系统至关重要，有助于检测可预测的明暗和温度周期。内源时钟的分子基础在整个生命树中是可变的，但它具有一个无所不在的属性：自然遗传多样性表现为例如假设的24小时最佳昼夜周期长度的变化。光周期的纬度变化不可能解释各种生物中记录的巨大多样性，但是我们尚未对时钟变异性与自然选择之间的相互作用有一个扎实的了解。最近对生物种群进行采样的昼夜节律研究引起了人们对野生遗传多样性的层次结构的关注，甚至揭示了在米级上明显的遗传变异。