Geographical or ecological divergence between the parapatric species Ephedra sinica and E. intermedia?

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• 作者：Hengxia Yin ; Xia Yan ; Wen Zhang ; Yong Shi ; Chaoju Qian…
• 关键词：Chloroplast DNA ; Ecological niche modelling ; Ephedra ; Isolation by environment ; Phylogeography
• 刊名：Plant Systematics and Evolution
• 出版年：2016
• 出版时间：October 2016
• 年：2016
• 卷：302
• 期：8
• 页码：1157-1170
• 全文大小：1,757 KB
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Life Sciences
  Plant Sciences
  Plant Ecology
  Plant Anatomy and Development
  Plant Systematics/Taxonomy/ Biogeography
  
• 出版者：Springer Wien
• ISSN：1615-6110
• 卷排序：302

文摘

Understanding the factors that contribute to population genetic structures and ecological niche divergence is crucial for elucidating the biogeographical history and speciation of plants. To disentangle the present phylogeographical patterns and evolutionary history of two closely related parapatric species from Ephedra (Ephedra sinica and E. intermedia), we systematically profiled their population genetic structures, niche divergence and potential speciation processes based on sequence variation of four chloroplast DNA fragments and climate-based ecological niche modelling (ENM). Phylogenetic analyses suggested that E. sinica formed a monophyly which was nested in E. intermedia. The latter species formed two paraphyletic subclades, corresponding to Western and Eastern lineages. Furthermore, the phylogeographical analysis results indicated very significant inter- and intra-species genetic differentiation, and BEAST inference suggested that E. sinica diverged from E. intermedia at 3.20 million years ago (Ma; 95 % HPD: 2.05–8.10 Ma), while the Western lineage of E. intermedia diverged much earlier at 6.10 Ma (95 % HPD: 4.10–11.82 Ma). In addition, niche identity tests performed using MaxEnt strongly supported the hypothesis that the two sister species had significantly diverged on their ecological niches. Isolation by geographical and environment distance (IBD and IBE) tests suggested that the overall divergence of the populations from the two species were more influenced by environmental factors. Our data provide new insight into the ecological speciation of Ephedra and also provides molecular evidence for the identification and genetic conservation of these important pharmaceutical plants.