The phoenix hypothesis of speciation
The phoenix hypothesis of speciation
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物种形成的凤凰假说
DOI：
10.1098/rspb.2022.1186
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
S.P.
中科院分区：
文献类型：
--
作者：
Yamaguchi;R. Wiley B.;and Otto;S.P.
随着时间的推移，异域种群之间的遗传差异会形成生殖隔离。当种群面临不断变化的环境时，这一过程会加速，这种环境允许大效应突变差异积累，但突然的变化也会使种群面临灭绝的风险。在这里，我们使用具有显式种群动态的费舍尔几何模型的模拟来探索面对环境变化时发生的遗传变化。由于进化拯救导致突变固定，与没有灭绝风险的种群相比，其表型效应平均更大，因此这些突变更有可能导致生殖隔离。我们把从数量下降的灰烬中形成新物种称为物种形成的凤凰假说。凤凰假说预测，在较高灭绝风险中幸存下来的种群中，混合适应性会出现更严重的崩溃。当许多位点是适应的基础时，这一假设得到了支持。然而，由于只有少量潜在的拯救突变，在不同群体中固定的突变更有可能是相同的，这种平行的变化减少了隔离。因此，鉴于可用于适应的突变数量有限，在面临中等灭绝风险的人群中，生殖隔离建立得最快。
Genetic divergence among allopatric populations builds reproductive isolation over time. This process is accelerated when populations face a changing environment that allows large-effect mutational differences to accumulate, but abrupt change also places populations at risk of extinction. Here we use simulations of Fisher's geometric model with explicit population dynamics to explore the genetic changes that occur in the face of environmental changes. Because evolutionary rescue leads to the fixation of mutations whose phenotypic effects are larger on average compared with populations not at risk of extinction, these mutations are thus more likely to lead to reproductive isolation. We refer to the formation of new species from the ashes of populations in decline as the phoenix hypothesis of speciation. The phoenix hypothesis predicts more substantial hybrid fitness breakdown among populations surviving a higher extinction risk. The hypothesis was supported when many loci underlie adaptation. With only a small number of potential rescue mutations, however, mutations that fixed in different populations were more likely to be identical, with such parallel changes reducing isolation. Consequently, reproductive isolation builds fastest in populations subject to an intermediate extinction risk, given a limited number of mutations available for adaptation.