Morphological and dietary changes encoded in the genome of Beroe ovata, a ctenophore-eating ctenophore

Abstract

As the sister group to all other animals, ctenophores (comb jellies) are important for understanding the emergence and diversification of numerous animal traits. Efforts to explore the evolutionary processes that promoted diversification within Ctenophora are hindered by undersampling genomic diversity within this clade. To address this gap, we present the sequence, assembly and initial annotation of the genome of Beroe ovata. Beroe possess unique morphology, behavior, ecology and development. Unlike their generalist carnivorous kin, beroid ctenophores feed exclusively on other ctenophores. Accordingly, our analyses revealed a loss of chitinase, an enzyme critical for the digestion of most non-ctenophore prey, but superfluous for ctenophorivores. Broadly, our genomic analysis revealed that extensive gene loss and changes in gene regulation have shaped the unique biology of B. ovata. Despite the gene losses in B. ovata, our phylogenetic analyses on photosensitive opsins and several early developmental regulatory genes show that these genes are conserved in B. ovata. This additional sampling contributes to a more complete reconstruction of the ctenophore ancestor and points to the need for extensive comparisons within this ancient and diverse clade of animals. To promote further exploration of these data, we present BovaDB (http://ryanlab.whitney.ufl.edu/bovadb/), a portal for the B. ovata genome.

Reproductive success of inbred strain MV31 of the ctenophoreMnemiopsis leidyiin a self-sustaining inland laboratory culture system

“…Ctenophores exhibit a number of interesting biological features, including regeneration [12][13][14][15], bi-oluminescence [16][17][18], rows of giant cilia used for locomotion [19][20][21], proprioceptive organs [22][23][24], immune cells [25][26][27], functional through-gut [28], prototypical nerve nets [29][30][31], and adaptations to extreme environments [32]. The genomes of several ctenophore species have now been sequenced and annotated [11,29,[33][34][35]. The varied and unusual morphologies of ctenophores have also made them popular for display in public aquariums [36].…”