Support for the evolutionary speed hypothesis from intraspecific population genetic data in the non-biting midge Chironomus riparius
Support for the evolutionary speed hypothesis from intraspecific population genetic data in the non-biting midge Chironomus riparius
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DOI：
10.1098/rspb.2015.2413
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发表时间：
2016-02
期刊：
影响因子：
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通讯作者：
Ann-Marie Oppold;J. Pedrosa;Miklós Bálint;J. Diogo;J. Ilkova;J. Pestana;M. Pfenninger
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文献类型：
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作者：
Ann-Marie Oppold;J. Pedrosa;Miklós Bálint;J. Diogo;J. Ilkova;J. Pestana;M. Pfenninger
进化速度假说（ESH）提出了纬度多样性梯度的因果机制。ESH的中心思想是，温度升高会导致世代时间缩短，突变率增加。在绝对时间尺度上，两者都应该导致选择和漂移的加速。基于ESH，我们开发了关于种内遗传多样性分布的预测：由于温暖的环境温度，每年有更多代的变温物种的种群应该彼此更加分化，积累更多的突变，并显示出与寒冷地区的种群相比突变率增加的证据。我们使用多化性昆虫物种摇蚊riparius来测试这些预测与细胞色素氧化酶I（COI）序列数据，发现从温暖地区的人口确实是显着更分化，并有显着更多的衍生单倍型比寒冷地区的人口。我们还发现，年平均温度与种群突变参数θ的显着相关性，在一定的假设下，作为每一代突变率的代理。这一模式可以证实与两个核基因座。总的来说，我们的研究结果支持ESH，并表明，经历的热制度可能是至关重要的驱动进化的外温动物，从而可能最终支配他们的物种形成率。
The evolutionary speed hypothesis (ESH) proposes a causal mechanism for the latitudinal diversity gradient. The central idea of the ESH is that warmer temperatures lead to shorter generation times and increased mutation rates. On an absolute time scale, both should lead to an acceleration of selection and drift. Based on the ESH, we developed predictions regarding the distribution of intraspecific genetic diversity: populations of ectothermic species with more generations per year owing to warmer ambient temperatures should be more differentiated from each other, accumulate more mutations and show evidence for increased mutation rates compared with populations in colder regions. We used the multivoltine insect species Chironomus riparius to test these predictions with cytochrome oxidase I (COI) sequence data and found that populations from warmer regions are indeed significantly more differentiated and have significantly more derived haplotypes than populations from colder regions. We also found a significant correlation of the annual mean temperature with the population mutation parameter θ that serves as a proxy for the per generation mutation rate under certain assumptions. This pattern could be corroborated with two nuclear loci. Overall, our results support the ESH and indicate that the thermal regime experienced may be crucially driving the evolution of ectotherms and may thus ultimately govern their speciation rate.