Department of Biology, Biodiversity Unit, Lund University, Lund 223 62, Sweden.
School of Biological Sciences, University of Portsmouth, Portsmouth PO1 2DY, UK.
Proc Natl Acad Sci U S A. 2023 Jan 3;120(1):e2203228120. doi: 10.1073/pnas.2203228120. Epub 2022 Dec 29.
Understanding the causes and limits of population divergence in phenotypic traits is a fundamental aim of evolutionary biology, with the potential to yield predictions of adaptation to environmental change. Reciprocal transplant experiments and the evaluation of optimality models suggest that local adaptation is common but not universal, and some studies suggest that trait divergence is highly constrained by genetic variances and covariances of complex phenotypes. We analyze a large database of population divergence in plants and evaluate whether evolutionary divergence scales positively with standing genetic variation within populations (evolvability), as expected if genetic constraints are evolutionarily important. We further evaluate differences in divergence and evolvability-divergence relationships between reproductive and vegetative traits and between selfing, mixed-mating, and outcrossing species, as these factors are expected to influence both patterns of selection and evolutionary potentials. Evolutionary divergence scaled positively with evolvability. Furthermore, trait divergence was greater for vegetative traits than for floral (reproductive) traits, but largely independent of the mating system. Jointly, these factors explained ~40% of the variance in evolutionary divergence. The consistency of the evolvability-divergence relationships across diverse species suggests substantial predictability of trait divergence. The results are also consistent with genetic constraints playing a role in evolutionary divergence.
了解表型特征的种群分歧的原因和限制是进化生物学的一个基本目标，它有可能预测对环境变化的适应。相互移植实验和最优模型的评估表明，局部适应很常见，但不是普遍的，一些研究表明，复杂表型的遗传方差和协方差高度限制了性状分歧。我们分析了一个关于植物种群分歧的大型数据库，并评估了进化分歧是否与种群内的遗传变异（可进化性）呈正相关，如果遗传限制在进化上很重要，这是可以预期的。我们进一步评估了有性生殖和无性生殖特征之间、自交、混合交配和异交物种之间的分歧和可进化性-分歧关系的差异，因为这些因素预计会影响选择模式和进化潜力。进化分歧与可进化性呈正相关。此外，与花（生殖）特征相比，无性繁殖特征的分歧更大，但与交配系统基本无关。这些因素共同解释了进化分歧方差的~40%。不同物种之间可进化性-分歧关系的一致性表明性状分歧具有相当大的可预测性。结果也与遗传限制在进化分歧中发挥作用的观点一致。
