The Opisthokonta and the Ecdysozoa may be clades: An update on Philip et al. (2005)

Abstract

To test the monophyly of Opisthokonta (animal-fungal clade) and Ecdysozoa (nematode-arthropod clade), Philip et al [Mol. Biol. Evol. 22: 1175–1184 (2005)] used sequence data from 10 eukaryotic genomes (an alveolate, a plant, two ascomycetous yeasts, a nematode, two dipterans, and three vertebrates). Strict criteria were used to select genes for phylogenetic analyses: single-gene families were identified and from these families, genes capable of recovering the uncontroversial parts of the phylogenetic tree (for example animal and vertebrate monophyly) were selected. Only five single-copy genes were found to be universally distributed across the analyzed taxa and capable of recovering all the uncontroversial parts of the tree. Phylogenetic analyses of those genes gave strong support for plant-animal grouping and the monophyly of Coelomata (vertebrate-arthropod grouping). Because numerous additional genome and EST projects have been completed since 2005, it is now possible to test the results of Philip et al using improved taxon sampling. Here, homologues of those five protein-coding genes (prefoldin 2, Tim22, U6 snRNP-associated protein, MAK16, and autophagocytosis protein) were obtained from sequence databases for additional taxa. Phylogenetic analyses of concatenation of those genes, using improved taxon sampling, recovered monophyly of Opisthokonta and Ecdysozoa, as well as Protostomia and Lophotrochozoa. These results again illustrate the importance of increased taxon sampling as shown in numerous previous studies using other datasets.