LAVROV, Dennis V.; LANG, B. Franz; Universite de Montreal; Universite de Montreal: Poriferan mtDNA and animal phylogeny based on mitochondrial gene arrangements

Phylogenetic relationships among the 30+ animal phyla are the subject of an ongoing controversy. Analysis of mitochondrial gene arrangements is well suited to investigate these relationships, however, its previous application outside of individual animal phyla has been hampered by the lack of informative out-group data. Here we report complete mitochondrial gene orders for two species representing the most basal animal phylum, the Porifera. With poriferans as an out-group, gene order analyses provide strong support for two major groups of bilaterian animals, the Protostomia and the Lophotrochozoa, and reveal remarkable mitochondrial gene order conservation in two other, the Deuterostomia and the Ecdysozoa.