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.

生物对重复出现的同质环境的适应，往往依托相似的表型策略得以实现。然而在此类情境中，自然选择（natural selection）是否同样会催生趋同进化（convergent evolution）的基因组改变，目前仍尚未明确。多变千里光（Senecio lautus）是研究趋同进化遗传基础的理想实验体系，因其形态相似的类群已在澳大利亚沿海的同质环境中完成适应性分化。本研究对该植物自然种群的全基因组分化（genomic divergence）模式开展了全分布范围的比较分析，并筛查了推测受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演化轨迹，涉及多个基因座（loci），这表明趋同适应既存在同一等位基因（allele）的平行招募现象，也存在不同地理种群间完全不同的基因组区域发生分化的情况。对候选基因（candidate genes）生物学功能的分析显示，该类群对沿海环境的适应，可能通过招募参与相似生物学过程的不同基因来实现。多变千里光类群平行演化所呈现的相对较低的基因组趋同性特征，表明在生物组织的更高层级上，演化过程更易受到约束。