Data from: A phylogenetic analysis of macroevolutionary patterns in fermentative yeasts

When novel sources of ecological opportunity are available, physiological innovations can trigger adaptive radiations. This could be the case of yeasts (Saccharomycotina), in which an evolutionary novelty is represented by the capacity to exploit simple sugars from fruits (fermentation). During adaptive radiations, diversification and morphological evolution are predicted to slow-down after early bursts of diversification. Here, we performed the first comparative phylogenetic analysis in yeasts, testing the “early burst” prediction on species diversification and also on traits of putative ecological relevance (cell-size and fermentation versatility). We found that speciation rates are constant during the time-range we considered (ca., 150 millions of years). Phylogenetic signal of both traits was significant (but lower for cell-size), suggesting that lineages resemble each other in trait-values. Disparity analysis suggested accelerated evolution (diversification in trait values above Brownian Motion expectations) in cell-size. We also found a significant phylogenetic regression between cell-size and fermentation versatility (R2 = 0.10), which suggests correlated evolution between both traits. Overall, our results do not support the early burst prediction both in species and traits, but suggest a number of interesting evolutionary patterns, that warrant further exploration. For instance, we show that the Whole Genomic Duplication that affected a whole clade of yeasts, does not seems to have a statistically detectable phenotypic effect at our level of analysis. In this regard, further studies of fermentation under common-garden conditions combined with comparative analyses are warranted.

当全新的生态机遇来源出现时，生理学创新可触发适应辐射。酵母菌（酵母亚门Saccharomycotina）便是典型案例，其演化创新体现为利用果实中的单糖进行发酵的能力。在适应辐射过程中，物种分化与形态演化预计会在早期分化爆发后趋于放缓。本研究首次针对酵母菌开展比较系统发育分析，既检验了物种分化的"早期爆发"假说，也对若干具有潜在生态相关性的性状（细胞大小与发酵多功能性）进行了验证。我们发现，在所考察的约1.5亿年时间范围内，物种形成速率保持恒定。两项性状的系统发育信号均显著（细胞大小的信号相对较弱），表明同一演化支系的性状值具有相似性。性状差异分析显示，细胞大小的演化速率有所加快——其性状值的分化程度高于布朗运动预期水平。我们还发现细胞大小与发酵多功能性之间存在显著的系统发育回归关系（决定系数R²=0.10），这表明二者存在协同演化。总体而言，我们的研究结果既不支持物种分化也不支持性状演化的早期爆发假说，但揭示了若干值得进一步探索的有趣演化模式。例如，我们发现，影响整个酵母演化支系的全基因组复制（Whole Genomic Duplication），在本研究的分析尺度下未表现出可被统计检测到的表型效应。就此而言，未来需开展结合同质园共同培养条件与比较分析的发酵相关研究。