Phylogeographic analysis of Saxifraga fortunei complex (Saxifragaceae) reveals multiple origins of morphological and ecological variations in the Japanese Archipelago
Phylogeographic analysis of Saxifraga fortunei complex (Saxifragaceae) reveals multiple origins of morphological and ecological variations in the Japanese Archipelago
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DOI：
10.1016/j.ympev.2021.107230
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发表时间：
2021-06-28
影响因子：
4.1
通讯作者：
Setoguchi, Hiroaki
中科院分区：
文献类型：
--
作者：
Magota, Kana;Sakaguchi, Shota;Setoguchi, Hiroaki
一个物种内的表型多态性是进化生物学中一个值得注意的现象，有助于理解适应性物种形成过程和其他历史事件。虎耳草（Saxifraga fortunei）复合群是一种在东亚广泛分布的草本植物。它包括几个与其栖息环境相对应的生态型分类群。各种生态型在日本群岛有限区域内的分布使得该物种成为研究种群动态历史和自然选择对谱系多样化影响的合适模型。在此，基于桑格测序的方法被用于估算欧亚大陆和日本种群之间的分化时间框架。通过双酶切简化基因组测序（ddRAD sequencing）获得的全基因组单核苷酸多态性（SNPs）被用于研究生态型分类群的系统地理起源。系统发育分析揭示日本种群在中新世晚期从大陆种群中分化出来。确定了日本北部和南部两个不同的区域分支；表型多样化仅在南部支系中明显。日本南部支系呈现出从北向南的历史分布扩张。表型变异似乎是在扩张过程中产生的。生态型界限与遗传分组不一致。我们提出日本种群的形态和生态特化是由当地自然选择反复产生的。
Phenotypic polymorphism within a species is a notable phenomenon in evolutionary biology to understand the process of adaptive speciation and other historical events. The Saxifraga fortunei complex is a widespread herb found in East Asia. It includes several ecotypic taxa corresponding to their habitat environments. The distribution of the various ecotypes in a limited area of the Japanese Archipelago makes the species a suitable model to investigate the impact of population demographic history and natural selection on lineage diversification. Here, Sanger-based sequencing was used to estimate the divergence timeframe between populations of the Eurasian continent and Japan. Genome-wide SNPs obtained by ddRAD sequencing were used to investigate the phylogeographic origins of ecotypic taxa. The phylogenetic analyses revealed the divergence of the Japanese population from the continental population in the late Miocene. Two distinct regional clades of North and South Japan were identified; phenotypic diversification was evident only in the southern clade. The South Japan clades displayed a historical distribution expansion from north to south. The phenotypic variations appeared to have generated during the expansion. The ecotypic boundaries were incongruent with the genetic grouping. We propose that morphological and ecological specialization in Japanese populations was repeatedly generated by local natural selection.