Koubínová Darina, Dincă Vlad, Dapporto Leonardo, Vodă Raluca, Suchan Tomasz, Vila Roger, Alvarez Nadir
Department of Ecology and Evolution, Faculty of Biology and Medicine, University of Lausanne, Biophore, 1015, Lausanne, Switzerland.
Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Passeig Marítim de la Barceloneta, 37, 08003, Barcelona, Spain.
Sci Rep. 2017 Oct 23;7(1):13752. doi: 10.1038/s41598-017-12938-8.
Biotic interactions are often acknowledged as catalysers of genetic divergence and eventual explanation of processes driving species richness. We address the question, whether extreme ecological specialization is always associated with lineage sorting, by analysing polymorphisms in morphologically similar ecotypes of the myrmecophilous butterfly Maculinea alcon. The ecotypes occur in either hygric or xeric habitats, use different larval host plants and ant species, but no significant distinctive molecular traits have been revealed so far. We apply genome-wide RAD-sequencing to specimens originating from both habitats across Europe in order to get a view of the potential evolutionary processes at work. Our results confirm that genetic variation is mainly structured geographically but not ecologically - specimens from close localities are more related to each other than populations of each ecotype from distant localities. However, we found two loci for which the association with xeric versus hygric habitats is supported by segregating alleles, suggesting convergent evolution of habitat preference. Thus, ecological divergence between the forms probably does not represent an early stage of speciation, but may result from independent recurring adaptations involving few genes. We discuss the implications of these results for conservation and suggest preserving biotic interactions and main genetic clusters.
生物相互作用通常被认为是遗传分化的催化剂，也是驱动物种丰富度的过程的最终解释。我们通过分析嗜蚁蝴蝶Maculinea alcon形态相似的生态型中的多态性，来探讨极端生态特化是否总是与谱系分选相关的问题。这些生态型出现在潮湿或干旱的栖息地，使用不同的幼虫寄主植物和蚂蚁物种，但到目前为止尚未发现明显的独特分子特征。我们对来自欧洲各地这两种栖息地的标本进行全基因组RAD测序，以便了解潜在的进化过程。我们的结果证实，遗传变异主要在地理上而非生态上结构化——来自相近地点的标本比来自遥远地点的每种生态型的种群彼此之间的关系更密切。然而，我们发现了两个位点，其与干旱与潮湿栖息地的关联得到了分离等位基因的支持，这表明栖息地偏好的趋同进化。因此，这些形态之间的生态分化可能并不代表物种形成的早期阶段，而是可能源于涉及少数基因的独立反复适应。我们讨论了这些结果对保护的意义，并建议保护生物相互作用和主要的遗传簇。
