Comparative transcriptomics provides insights into reticulate and adaptive evolution of a butterfly radiation

Butterfly eyes are complex organs that are composed of a diversity of proteins and they play a central role in visual signaling and ultimately, speciation and adaptation. Here, we utilized the whole eye transcriptome to obtain a more holistic view of the evolution of the butterfly eye while accounting for speciation events that co-occur with ancient hybridization. We sequenced and assembled transcriptomes from adult female eyes of eight species representing all major clades of the Heliconius genus and an additional outgroup species, Dryas iulia. We identified 4042 orthologous genes shared across all transcriptome datasets and constructed a transcriptome-wide phylogeny, which revealed topological discordance with the mitochondrial phylogenetic tree in the Heliconius pupal mating clade. We then estimated introgression among lineages using additional genome data and found evidence for ancient hybridization leading to the common ancestor of H. hortense and H. clysonymus. We estimated the Ka...

蝴蝶眼睛是由多种蛋白质构成的复杂器官，在视觉信号转导乃至物种形成与适应性演化过程中发挥核心作用。本研究借助完整眼部转录组（whole eye transcriptome），旨在更全面地解析蝴蝶眼睛的演化历程，同时兼顾与古老杂交事件相伴的物种形成过程。我们对代表袖蝶属（Heliconius）所有主要演化支（clades）的8个物种，以及1个外类群物种茱莉亚釉蛱蝶（Dryas iulia）的成年雌性眼部转录组进行了测序与组装。我们鉴定出所有转录组数据集共有的4042个直系同源基因（orthologous genes），并构建了全转录组水平的系统发育树（transcriptome-wide phylogeny），结果显示，袖蝶属蛹交演化支（pupal mating clade）的拓扑结构与线粒体系统发育树存在不一致性。随后，我们利用额外的基因组数据评估了各谱系间的基因渐渗（introgression）情况，发现存在古老杂交事件的证据，该事件造就了H. hortense与H. clysonymus的共同祖先。我们估算了Ka……