Austrian Academy of Sciences, Gregor Mendel Institute of Plant Biology, Vienna, Austria.
Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.
Mol Ecol. 2020 Apr;29(8):1399-1401. doi: 10.1111/mec.15391. Epub 2020 Mar 12.
Independent or parallel evolution of similar traits is key to understanding the genetics and limitations of adaptation. Adaptation from the same genetic changes in different populations defines parallel evolution. Such genetic changes can derive from standing ancestral variation or de novo mutations and excludes instances of adaptive introgression. In this issue of Molecular Ecology, Walden et al.(2020) investigate the scale of parallel climate adaptation from standing genetic variation between two North American Arabidopsis lyrata lineages, each formed by a distinct evolutionary history during the last glacial cycle. By identifying adaptive variants correlated with three ecologically significant climatic gradients, they show that instead of the same genetic variants or even genes, parallel evolution is only observed at the level of biological processes. The evolution of independent adaptive variants to climate in two genetically close lineages is explained by their different post-glacial demographic histories. Separate glacial refugia and strong population bottlenecks were probably sufficient to change the landscape of shared allele frequencies, hindering the possibility of parallel evolution.
独立或平行进化的相似特征是理解遗传和适应限制的关键。来自不同种群中相同遗传变化的适应被定义为平行进化。这种遗传变化可以源于祖先的遗传变异或新的突变，并且排除了适应性渗入的情况。在本期《分子生态学》中，Walden 等人（2020 年）研究了来自两个北美拟南芥 lyrata 谱系之间的遗传变异的平行气候适应的程度，这两个谱系分别是在上一个冰河时代期间由不同的进化历史形成的。通过鉴定与三个生态上重要的气候梯度相关的适应性变体，他们表明，平行进化仅在生物过程的水平上观察到，而不是相同的遗传变体甚至基因。两个遗传上密切相关的谱系中对气候的独立适应性变体的进化，是由它们不同的冰河后种群历史所解释的。不同的冰河避难所和强烈的种群瓶颈可能足以改变共同等位基因频率的景观，从而阻碍了平行进化的可能性。
