D3157: Assembling the genome of the evolutionary relic, the petal tail dragonfly, Tanypteryx hageni

Although relatively little genomic research has been conducted on ancient lineages, available data reveals several interesting patterns. Assemblies of the Giant Lungfish (Meyer et al. 2021), Mangrove Horseshoe Crab (Shingate et al. 2020), Ginko Biloba Tree (Guan et al. 2016) and African Coelacanth (Amemiya et al. 2013) reveal convergence upon a relatively large genome size, expanded immune gene families, high repeat content, and, in the case of metazoans, expanded hox clusters. Despite containing a large portion of the earth’s biodiversity, little is known about the genomes of ancient lineages in the class Insecta. To investigate whether ancient insect lineages share the traits of other ancient metazoan lineages, we assembled the genome of the anisopteran Tanypteryx hageni, commonly known as the black petalitail, using PacBio Hi-Fi sequencing technology. We found that the genome of Tanypteryx contains an unusually high repeat content, and its size is above average compared to other anisopterans. Additionally, a PSMC analysis revealed a pattern of a decreasing effective population size in cooling periods, complemented by rebounds in warming periods. We also compared immune and hox gene families in Tanypteryx to those of the zygopteran Archilestes grandis (Great Spreadwing). Here, we discuss how these results shed light on the genomic adaptations of both ancient lineages, and odonates.