Deep Ancestral Introgression Shapes Evolutionary History of Dragonflies and Damselflies

Introgression is an important biological process affecting at least 10% of the extant species in the animal kingdom. Introgression significantly impacts inference of phylogenetic species relationships where a strictly binary tree model cannot adequately explain reticulate net-like species relationships. Here, we use phylogenomic approaches to understand patterns of introgression along the evolutionary history of a unique, nonmodel insect system: dragonflies and damselflies (Odonata). We demonstrate that introgression is a pervasive evolutionary force across various taxonomic levels within Odonata. In particular, we show that the morphologically intermediate species of Anisozygoptera (one of the three primary suborders within Odonata besides Zygoptera and Anisoptera), which retain phenotypic characteristics of the other two suborders, experienced high levels of introgression likely coming from zygopteran genomes. Additionally, we find evidence for multiple cases of deep inter-superfamilial ancestral introgression. [Gene flow; Odonata; phylogenomics; reticulate evolution.]

Automated summary

Introgression is an important biological process affecting the evolution of various taxonomic levels within Odonata, with evidence of deep inter-superfamilial ancestral introgression. Morphologically intermediate species of Anisozygoptera experienced high levels of introgression likely from zygopteran genomes, highlighting the pervasive nature of introgression in dragonflies and damselflies.