Data from: Convergence and divergence during the adaptation to similar environments by an Australian groundsel

Adaptation to replicate environments is often achieved through similar phenotypic solutions. Whether selection also produces convergent genomic changes in these situations remains largely unknown. The variable groundsel, Senecio lautus, is an excellent system to investigate the genetic underpinnings of convergent evolution, since morphologically similar forms of these plants have adapted to the same environments along the coast of Australia. We compared range-wide patterns of genomic divergence in natural populations of this plant and searched for regions putatively affected by natural selection. Our results indicate that environmental adaptation followed complex genetic trajectories, affecting multiple loci, implying both the parallel recruitment of the same alleles and the divergence of completely different genomic regions across geography. An analysis of the biological functions of candidate genes suggests that adaptation to coastal environments may have occurred through the recruitment of different genes participating in similar processes. The relatively low genetic convergence that characterizes the parallel evolution of S. lautus forms suggests that evolution is more constrained at higher levels of biological organization.

生物适应重复出现的同类环境时，通常会采用相似的表型策略。而在此类情境中，自然选择是否也会催生趋同进化（convergent evolution）的基因组改变，目前仍不甚明晰。异叶千里光（Senecio lautus）是研究趋同进化遗传基础的绝佳实验体系，因为该物种的多个形态相似类群，均已适应澳大利亚沿海的同类生境。本研究对该植物自然种群的全分布范围基因组分化模式进行了比较分析，并搜寻了推定受到自然选择影响的基因组区域。研究结果显示，环境适应遵循复杂的遗传路径，涉及多个基因座，这意味着既存在同一等位基因的平行招募现象，也存在不同地理区域间出现完全不同的基因组区域分化的情形。对候选基因（candidate genes）生物学功能的分析表明，对沿海生境的适应，可能通过招募参与同类生物学过程的不同基因来实现。异叶千里光类群的平行进化呈现出较低水平的基因组趋同性，这表明在更高层级的生物组织层次上，进化过程更易受到约束。