Meeting Abstract
Opsins are photosensitive proteins widely used for light sensing in animals. Opsin diversity in non-Bilaterian animals is key for our understanding of this gene family’s evolution and the evolution of eyes and light sensitivity. Nonetheless, opsins in non-Bilaterians are poorly known. Previous work with comparatively limited taxon-sampling suggested that cnidarians express three ancient opsin subfamilies (Anthozoa II, chaopsins and xenopsins – which includes the well-established cnidops). Opsin genes from representatives of Xenacoelomorpha (the sister group to other bilaterians) have not been studied so far. To improve taxon sampling of opsin studies, we screened publicly available and newly generated transcriptomes from 35 cnidarians of all major groups (except for Staurozoa), and 4 xenacoelomorphs. Following the protocol described in Ramirez et al. (2016), we retrieved 106 cnidarian and 17 xenacoelomorph opsin sequences. We corroborate that cnidarians consistently express opsins belonging to the groups Anthozoa II, Chaopsin and Xenopsin (Cnidops) as recognized by Ramirez et al. (2016). Like Anthozoa II opsins, cnidarian chaopsins are also only expressed by anthozoans.We show that multiple ancient gene duplications and losses of cnidops paralogs occurred during cnidarian history. Xenacoelomorphs express non-canonical r-opsins similar to those found in other bilaterians. Besides strongly supporting recently recognized opsin groups, our extended dataset provide further insights into opsin evolution in non-Bilaterian animals.
