Departament de Genètica, Microbiologia i Estadística, Facultat de Biologia and Institut de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona, Barcelona, Spain.
Laboratory for Integrative Biodiversity Research, Finnish Museum of Natural History, University of Helsinki, Helsinki, Finland.
Mol Ecol. 2019 Sep;28(17):4028-4045. doi: 10.1111/mec.15199. Epub 2019 Aug 19.
The coexistence of multiple eco-phenotypes in independently assembled communities makes island adaptive radiations the ideal framework to test convergence and parallelism in evolution. In the radiation of the spider genus Dysdera in the Canary Islands, species diversification occurs concomitant with repeated events of trophic specialization. These dietary shifts, to feed primarily on woodlice, are accompanied by modifications in morphology (mostly in the mouthparts), behaviour and nutritional physiology. To gain insight into the molecular basis of this adaptive radiation, we performed a comprehensive comparative transcriptome analysis of five Canary Island Dysdera endemics representing two evolutionary and geographically independent events of dietary specialization. After controlling for the potential confounding effects of hemiplasy, our differential gene expression and selective constraint analyses identified a number of genetic changes that could be associated with the repeated adaptations to specialized diet of woodlice, including some related to heavy metal detoxification and homeostasis, the metabolism of some important nutrients and venom toxins. Our results shed light on the genomic basis of an extraordinary case of dietary shift convergence associated with species diversification. We uncovered putative molecular substrates of convergent evolutionary changes at different hierarchical levels, including specific genes, genes with equivalent functions and even particular amino acid positions. This study improves our knowledge of rapid adaptive radiations and provides new insights into the predictability of evolution.
在独立组装的群落中存在多种生态表型，这使得岛屿适应辐射成为检验进化中趋同和并行的理想框架。在加那利群岛的狼蛛属 Dysdera 的辐射中，物种多样化伴随着营养特化的反复事件发生。这些饮食的转变，主要以食木虱为食，伴随着形态（主要在口器部分）、行为和营养生理学的改变。为了深入了解这种适应性辐射的分子基础，我们对代表两次独立的进化和地理事件的五种加那利群岛 Dysdera 特有种进行了全面的比较转录组分析。在控制半同态的潜在混杂效应后，我们的差异基因表达和选择约束分析确定了一些与反复适应食木虱的专门饮食相关的遗传变化，包括一些与重金属解毒和内稳态、一些重要营养物质和毒液毒素代谢相关的变化。我们的研究结果阐明了与物种多样化相关的特殊饮食趋同适应的基因组基础。我们揭示了不同层次的趋同进化变化的潜在分子基质，包括特定基因、具有等效功能的基因，甚至特定的氨基酸位置。这项研究提高了我们对快速适应性辐射的认识，并为进化的可预测性提供了新的见解。
