No evidence of intrinsic reproductive isolation between two reciprocally non-monophyletic, ecologically differentiated mountain plants at an early stage of speciation

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• 作者：Clara Bertel ; Karl Hülber ; Božo Frajman ; Peter Schönswetter
• 关键词：Controlled cross ; pollinations ; Ecological speciation ; Ecotypes ; Heliosperma pusillum ; Homoploid non ; hybrid speciation ; Incomplete reproductive isolation ; Speciation continuum
• 刊名：Evolutionary Ecology
• 出版年：2016
• 出版时间：December 2016
• 年：2016
• 卷：30
• 期：6
• 页码：1031-1042
• 全文大小：490 KB
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Life Sciences
  Evolutionary Biology
  Plant Sciences
  Human Genetics
  
• 出版者：Springer Netherlands
• ISSN：1573-8477
• 卷排序：30

文摘

Adaptation to dissimilar habitats can trigger phenotypic and genetic differences between populations, which may, in the absence of gene flow, ultimately lead to ecological speciation. Reproductive isolation of diverging populations is a critical step at the onset of speciation. An excellent example for exploring the extent of reproductive isolation at early stages of speciation is provided by Heliosperma pusillum and H. veselskyi (Caryophyllaceae), two reciprocally non-monophyletic, ecologically differentiated species from the Alps. Interspecific gene flow—as revealed by recent genetic studies—is rare even between geographically close populations. Cross pollinations and fitness experiments revealed no evidence of intrinsic reproductive barriers, since fitness parameters measured under uniform conditions were not lower in inter- than in intraspecific crosses. Further, morphometric analyses of the offspring clearly showed that the differentiation of parental species is heritable. As parental phenotypes are likely adaptive, the intermediate morphology of hybrids may lead to reduced hybrid fitness in parental habitats. Altogether, H. pusillum and H. veselskyi provide an increasingly well characterised model system offering exciting insights into early stages of ecological speciation.