Meeting Abstract

P3.45  Wednesday, Jan. 6  Cnidarian tree of life based on mitochondrial genomic data KAYAL, E*; LAVROV, DV; Iowa State University; Iowa State University ehsan.kayal@gmail.com

Mitochondrial DNA (mtDNA) is one of the most informative and popular molecular markers in animal phylogenetics. In addition to the large amount of sequence data, it contains other phylogenetically-informative characters including genome architecture, gene order, and genetic code. The overall structure of mtDNA (circular vs. linear) was one of the original molecular characters used to subdivide the phylum Cnidaria into two large subgroups: Anthozoa and Medusozoa. Anthozoan have single and circular mtDNA molecules. In Medusozoa, the mitochondrial genome can consist of one, two or more stable linear molecules. While sequencing circular mtDNA became a routine procedure in the last decade, sequencing linear mtDNA presents a challenge as illustrated by only three published linear mitochondrial genomes for Medusozoa in comparison to 34 circular genomes for Anthozoa. We amplified and sequenced nearly complete linear mtDNA genomes from several species representing three Medusozoa classes: Hydrozoa, Scyphozoa and Stauromedusa. Here we present a quick comparative analysis of these genomes with respect to the number of molecules, gene order and gene content. Furthermore, by investigating the sequences we found conserved class-specific features at the ends of the linear chromosome(s) of all Medusozoan mtDNAs. Our data support previously published phylogenetic relationships within a monophyletic Medusozoa group. Moreover, we provide additional support for the paraphyly of Anthozoa with Octocorallia as the sister group to Medusozoa. Finally, we suggest that additional linear mitochondrial genomes from Medusozoa, and particularly Cubozoa will help resolving the phylogeny of Cnidaria. This will also provide insights for understanding the linearization of mtDNA in this group.