Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, 48109, USA.
Present address: Department of Quantitative and Computational Biology, University of Southern California, Los Angeles, CA, 90089, USA.
BMC Ecol Evol. 2023 Sep 12;23(1):50. doi: 10.1186/s12862-023-02164-4.
No phenotypic trait evolves independently of all other traits, but the cause of trait-trait coevolution is poorly understood. While the coevolution could arise simply from pleiotropic mutations that simultaneously affect the traits concerned, it could also result from multivariate natural selection favoring certain trait relationships. To gain a general mechanistic understanding of trait-trait coevolution, we examine the evolution of 220 cell morphology traits across 16 natural strains of the yeast Saccharomyces cerevisiae and the evolution of 24 wing morphology traits across 110 fly species of the family Drosophilidae, along with the variations of these traits among gene deletion or mutation accumulation lines (a.k.a. mutants). For numerous trait pairs, the phenotypic correlation among evolutionary lineages differs significantly from that among mutants. Specifically, we find hundreds of cases where the evolutionary correlation between traits is strengthened or reversed relative to the mutational correlation, which, according to our population genetic simulation, is likely caused by multivariate selection. Furthermore, we detect selection for enhanced modularity of the yeast traits analyzed. Together, these results demonstrate that trait-trait coevolution is shaped by natural selection and suggest that the pleiotropic structure of mutation is not optimal. Because the morphological traits analyzed here are chosen largely because of their measurability and thereby are not expected to be biased with regard to natural selection, our conclusion is likely general.
没有任何表型特征是独立于所有其他特征进化的，但特征-特征协同进化的原因还不清楚。虽然协同进化可能仅仅是由于同时影响相关特征的多效突变引起的，但也可能是由于多变量自然选择有利于某些特征关系而导致的。为了从机制上全面了解特征-特征协同进化，我们研究了 16 个酿酒酵母自然菌株的 220 个细胞形态特征的进化，以及 110 个果蝇科果蝇物种的 24 个翅膀形态特征的进化，以及这些特征在基因缺失或突变积累系（也称为突变体）中的变化。对于许多特征对，进化谱系之间的表型相关性与突变体之间的相关性显著不同。具体来说，我们发现了数百种情况，即相对于突变相关性，特征之间的进化相关性得到了加强或逆转，根据我们的群体遗传模拟，这很可能是多变量选择的结果。此外，我们还检测到酵母特征分析中增强模块性的选择。总之，这些结果表明，特征-特征协同进化是由自然选择塑造的，并表明突变的多效结构不是最优的。由于这里分析的形态特征主要是因为它们的可测量性，因此预计不会偏向于自然选择，因此我们的结论可能是普遍的。
