Gene rearrangements in the mitochondrial genome of ten ascaris species and phylogenetic implications for Ascaridoidea and Heterakoidea families

The Ascaridoidea family and Heterakoidea family are the most common and typical representative of large parasites. Although our understanding of these parasites' diversity has expanded by analyses of some mito-chondrial genes, there is limited information on these species' evolutionary rates. Here we determined ten complete mitogenome sequences of five subfamilies of Ascaridoidea and one subfamily of Heterakoidea. The phylogenetic tree divided the Ascaridoidea into six monophyletic major clades, and the divergence time of Heterakoidea family and Ascaridoidea family can be placed during the early Carboniferous Period (300-360 Mya). The reconstruction of the ancestral state showed that the gene orders of all species in Ascaridoidea were conserved, and the Heterakoidea had obvious genome rearrangement. The conserved blocks between them were divided into five and the main types are tandem-duplication/random loss (TDRL). These results will help to better understand the gene rearrangements and evolutionary position of ascaris species.

Automated summary

This study expands our understanding of the diversity and evolutionary rates of the Ascaridoidea and Heterakoidea families through analyses of mitochondrial genes. The phylogenetic tree divides the Ascaridoidea into six major clades, and the divergence time of the Heterakoidea and Ascaridoidea families can be traced back to the early Carboniferous Period. The gene orders of the Ascaridoidea species are conserved, while the Heterakoidea species exhibit genome rearrangements.