A mirage of cryptic species: genomics uncover striking mito-nuclear discordance in the butterfly Thymelicus sylvestris

Mitochondrial DNA (mtDNA) sequencing has led to an unprecedented rise in the identification of cryptic species. However, it is widely acknowledged that nuclear DNA (nuDNA) sequence data are also necessary to properly define species boundaries. Next generation sequencing techniques provide a wealth of nuclear genomic data, which can be used to ascertain both the evolutionary history and taxonomic status of putative cryptic species. Here, we focus on the intriguing case of the butterfly Thymelicus sylvestris (Lepidoptera: Hesperiidae). We identified six deeply diverged mitochondrial lineages; three distributed all across Europe and found in sympatry, suggesting a potential case of cryptic species. We then sequenced these six lineages using double-digest restriction-site associated DNA sequencing (ddRADseq). Nuclear genomic loci contradicted mtDNA patterns and genotypes generally clustered according to geography, i.e., a pattern expected under the assumption of postglacial recolonization f...

线粒体DNA（mtDNA）测序技术推动了隐存物种识别数量的空前增长。然而学界普遍认为，要合理界定物种边界，核DNA（nuDNA）序列数据同样不可或缺。下一代测序技术可产生海量核基因组数据，既能用以推定疑似隐存物种的演化历史，也能明确其分类地位。本研究聚焦于林小弄蝶（Thymelicus sylvestris，鳞翅目：弄蝶科）这一极具研究价值的类群。我们共识别出6个深度分化的线粒体谱系，其中3个广泛分布于欧洲且呈同域分布，这提示该类群可能存在隐存物种。随后我们采用双酶切限制性位点相关DNA测序（ddRADseq）技术对这6个谱系进行了测序分析。核基因组位点的结果与线粒体DNA的模式并不一致，基因型总体上呈现地理聚类特征，即冰期后回迁假说下预期的演化模式……