Phylogeographic and demographic modelling analyses of the multiple origins of the rheophytic goldenrod Solidago yokusaiana

Understanding adaptation mechanisms is important in evolutionary biology. Parallel adaptation provides good opportunities to investigate adaptive evolution. To confirm parallel adaptation, it is effective to examine whether the phenotypic similarity has one or multiple origins and to use demographic modelling to consider the gene flow between ecotypes. Solidago yokusaiana is a rheophyte endemic to the Japanese Archipelago that diverged from Solidago virgaurea. This study examined the parallel origins of S. yokusaiana by distinguishing between multiple and single origins and subsequent gene flow. The haplotypes of non-coding chloroplast DNA and genotypes at 14 nuclear simple sequence repeat (nSSR) loci and single nucleotide polymorphisms (SNPs) revealed by double-digest restriction-associated DNA sequencing (ddRADseq) were used for phylogeographic analysis; the SNPs were also used to model population demographics. Some chloroplast haplotypes were common to S. yokusaiana and its ancestor ...在进化生物学领域，解析适应机制具有核心研究价值。平行适应为探究适应性进化的内在规律提供了绝佳的研究契机。若要验证平行适应现象，可通过两种高效途径开展研究：一是探究表型相似性的起源为单一还是多重来源，二是借助种群动态建模分析不同生态型间的基因流。Solidago yokusaiana是特有分布于日本列岛的溪生植物，其演化自Solidago virgaurea。本研究通过区分多重起源与单一起源两种情形，并探究后续发生的基因流，以此解析Solidago yokusaiana的平行起源问题。研究采用了非编码叶绿体DNA单倍型、14个核简单序列重复（nuclear simple sequence repeat, nSSR）位点的基因型数据，以及通过双酶切限制性位点相关DNA测序（double-digest restriction-associated DNA sequencing, ddRADseq）获得的单核苷酸多态性（single nucleotide polymorphisms, SNPs）开展系统地理学分析；同时利用SNPs数据构建种群动态模型。部分叶绿体单倍型为Solidago yokusaiana与其祖先种所共有……