Nuclear genome annotation of wheel animals and thorny-headed worms: inferences about the last common ancestor of Syndermata (Rotifera s.l.)

Abstract The basal splits within Syndermata probably date back hundreds of millions years, and extant syndermatans greatly differ in reproduction modes (parthenogenesis, metagenesis, heterosexuality) lifestyles (free-living, epizoic, endoparasitic). Against this background, the present investigation aims to reconstruct genome transcriptome metrics last common ancestor (LCA) Syndermata. We especially annotated nuclear assemblies one representative, each, monogononts ( Brachionus plicatilis ), bdelloids Adineta vaga seisonids Seison nebaliae acanthocephalans Pomphorhynchus laevis S1 additionally considered previously published data. Present results suggest that syndermatan LCA possessed a compact 50–100 Mb with coding portion ≥ 40%. Its ~ 17,000 protein-coding genes had about 4–6 exons 3–5 introns on average. Long interspersed elements (LINEs) should have occupied 4–5% ancestral genome. Based this, independent evolutionary trajectories involving gene loss, duplication, repeat proliferation resulted varying genomes clade. Nevertheless, we identified 2114 clusters containing proteins all four taxa. About 200 these lacked sufficiently similar counterparts platyhelminths Macrostomum lignano Schmidtea mediterranea . Gene ontologies assigned might reference muscular pharynx, light perception, transposition, amongst others.