Meeting Abstract

59.4  Saturday, Jan. 5  The Genome of the Ctenophore, Mnemiopsis leidyi: Insights into the Genetics of Innovation and the Evolution of Multicellularity RYAN, J.F.; PANG, K.; SCHNITZLER, C.E.; KOCH, B.J.; NGUYEN, A.-D.; MORELAND, R.T.; MULLIKIN, J.C.; WOLFSBERG, T.G.; MARTINDALE, M.Q.; BAXEVANIS, A.D.*; NHGRI/NIH and Sars Intl. Centre for Marine Mol. Biol.; Kewalo Marine Lab, Univ. Hawaii; Natl. Human Genome Res. Inst., NIH; Natl. Human Genome Res. Inst., NIH; Natl. Human Genome Res. Inst., NIH; Natl. Human Genome Res. Inst., NIH; Natl. Human Genome Res. Inst., NIH; Natl. Human Genome Res. Inst., NIH; Kewalo Marine Lab, Univ. Hawaii; Natl. Human Genome Res. Inst., NIH andy@mail.nih.gov

Until recently, only three of the four non-bilaterian metazoan lineages had at least one species whose genome had been sequenced. Ctenophora (the comb jellies) remained as the last non-bilaterian animal phylum without a sequenced genome, and its phylogenetic position remained uncertain. To better-understand the molecular innovations that drove the outbreak of diversity and increasing complexity in the early evolution of animals, we sequenced, assembled, annotated, and performed a preliminary analysis of the 150-megabase genome of the ctenophore, Mnemiopsis. The availability of these high-quality, genome-scale data has enabled us to answer several important questions regarding phylogenetic diversity and the evolution of proteins that play a fundamental role in metazoan development. While many components of key protein families and regulatory pathways are present in Mnemiopsis, there are notable absences; for example, there are no discernible microRNAs in Mnemiopsis, and elements of the microprocessor complex are altogether missing. Continued analysis of the gene content of the earliest metazoan groups is helping to define which components were required for the origin of morphological complexity, and these data have provided a stronger foundation for resolving the question of the phylogenetic position of this phylum.