Which came first, the ctenophore or the sponge? New paper co-authored by Dr. Kocot helps settle the debate.

The phylum Ctenophora (comb jellies) consists of gelatinous, planktonic marine animals. Despite their somewhat unassuming nature, a fierce debate has been raging in the scientific literature about comb jellies as a number of genome-scale studies have suggested that ctenophores, and not the morphological simple sponges, are the sister group to all other animals. A new study published in Nature Ecology and Evolution co-authored by Dr. Kevin Kocot helps shed light on this question with new data spanning the diversity of Ctenophora. By sequencing expressed genes (transcriptomes) from 27 different species of comb jellies from all over the world that span most of the diversity of the group and conducing genome-scale phylogenetic analyses, the research team reconstructed the evolutionary history of the group and inferred the evolution of key ctenophore characters. Read a press release about this paper in UA News here and another in Discover Magazine here.