Cao Jia-Jia, Li Yi-Shao, Chang Chung-Te, Chung Jeng-Der, Hwang Shih-Ying
Department of Life Science, National Taiwan University, 1 Roosevelt Road, Section 4, Taipei 10617, Taiwan.
School of Life Science, National Taiwan Normal University, 88 Tingchow Road, Section 4, Taipei 11677, Taiwan.
Plants (Basel). 2022 Apr 30;11(9):1226. doi: 10.3390/plants11091226.
The testing association of environmental variables with genetic and epigenetic variation could be crucial to deciphering the effects of environmental factors playing roles as selective drivers in ecological speciation. Although ecological speciation may occur in closely related species, species boundaries may not be established over a short evolutionary timescale. Here, we investigated the genetic and epigenetic variations using amplified fragment length polymorphism (AFLP) and methylation-sensitive amplification polymorphism (MSAP), respectively, and tested their associations with environmental variables in populations of four closely related species in the complex. No distinctive species relationships were found using genetic clustering analyses, neighbor-joining tree, and neighbor-net tree based on the total AFLP variation, which is suggestive of the incomplete lineage sorting of ancestral variation. Nonetheless, strong isolation-by-environment and adaptive divergence were revealed, despite the significant isolation-by-distance. Annual mean temperature, elevation, normalized difference vegetation index, and annual total potential evapotranspiration were found to be the most important environmental variables explaining outlier genetic and epigenetic variations. Our results suggest that the four closely related species of the complex share the polymorphism of their ancestor, but reproductive isolation due to ecological speciation can occur if local environmental divergence persists over time.
将环境变量与遗传和表观遗传变异进行关联测试，对于解读环境因素作为生态物种形成中的选择驱动因素所产生的影响可能至关重要。尽管生态物种形成可能发生在亲缘关系密切的物种中，但物种界限可能不会在较短的进化时间尺度上确立。在此，我们分别使用扩增片段长度多态性（AFLP）和甲基化敏感扩增多态性（MSAP）研究了遗传和表观遗传变异，并测试了它们与该复合体中四个亲缘关系密切的物种群体中的环境变量的关联。基于总的AFLP变异，使用遗传聚类分析、邻接法树和邻域网树未发现明显的物种关系，这表明祖先变异的谱系分选不完全。尽管存在显著的距离隔离，但仍揭示出强烈的环境隔离和适应性分化。年平均温度、海拔、归一化植被指数和年总潜在蒸散量被发现是解释异常遗传和表观遗传变异的最重要环境变量。我们的结果表明，该复合体的四个亲缘关系密切物种共享其祖先的多态性，但如果局部环境差异长期存在，由于生态物种形成可能会发生生殖隔离。
