High levels of chromosomal synteny in 250 million year old groups of dragonflies and damselflies (Insecta:Odonata)

Abstract Using recently published chromosome-length genome assemblies of damselfly species Ischnura elegans and Platycnemis pennipes and dragonfly species Pantala flavescens and Tanypteryx hageni , we demonstrate that the autosomes of Odonata show a high level of conservation, despite 250 million years of separation. In the four genomes discussed here, our results show that all autosomes have a clear homolog to the ancestral karyotype. Despite clear synteny, we demonstrate that different factors, including concentration of repeat dynamics, GC content, and the relative proportion of coding sequence all influence the amount of synteny across chromosomes, and that the influence of these factors differ among species. Micro- and sex chromosomes in Odonata do not share the same level of synteny as autosomes. Of the four species sampled, the genome of the Black Petaltail, which diverged from its sister species 70 million years ago, is a clear outlier, showing similarities to other long-lived lineages.