Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden.
Swedish Collegium of Advanced Study, Uppsala University, Uppsala, Sweden.
Mol Biol Evol. 2023 Nov 3;40(11). doi: 10.1093/molbev/msad228.
New mutations provide the raw material for evolution and adaptation. The distribution of fitness effects (DFE) describes the spectrum of effects of new mutations that can occur along a genome, and is, therefore, of vital interest in evolutionary biology. Recent work has uncovered striking similarities in the DFE between closely related species, prompting us to ask whether there is variation in the DFE among populations of the same species, or among species with different degrees of divergence, that is whether there is variation in the DFE at different levels of evolution. Using exome capture data from six tree species sampled across Europe we characterized the DFE for multiple species, and for each species, multiple populations, and investigated the factors potentially influencing the DFE, such as demography, population divergence, and genetic background. We find statistical support for the presence of variation in the DFE at the species level, even among relatively closely related species. However, we find very little difference at the population level, suggesting that differences in the DFE are primarily driven by deep features of species biology, and those evolutionarily recent events, such as demographic changes and local adaptation, have little impact.
新的突变提供了进化和适应的原材料。适应度效应分布（DFE）描述了基因组上可能发生的新突变的效应谱，因此在进化生物学中具有至关重要的意义。最近的研究揭示了密切相关的物种之间 DFE 的惊人相似性，促使我们提出这样一个问题：在同一物种的不同种群之间，或者在具有不同分歧程度的物种之间，DFE 是否存在差异，即 DFE 是否在不同的进化水平上存在差异。我们利用来自欧洲六个树种的外显子捕获数据，对多个物种的 DFE 进行了特征描述，并且对于每个物种，我们还对多个种群的 DFE 进行了研究，并调查了可能影响 DFE 的因素，例如种群动态、种群分歧和遗传背景。我们发现，即使在相对密切相关的物种之间，DFE 也存在着物种水平上的差异，这一结果具有统计学意义。然而，我们在种群水平上发现的差异非常小，这表明 DFE 的差异主要是由物种生物学的深层次特征驱动的，而那些进化上最近的事件，如种群动态变化和局部适应，几乎没有影响。
