Mitochondrial genome data support the basal position of Acoelomorpha and the polyphyly of the Platyhelminthes

Mol Phylogenet Evol. 2004 Nov;33(2):321-32. doi: 10.1016/j.ympev.2004.06.002.

Abstract

We determined 9.7, 5.2, and 6.8 kb, respectively, of the mitochondrial genomes of the acoel Paratomella rubra, the nemertodermatid Nemertoderma westbladi, and the free-living rhabditophoran platyhelminth Microstomum lineare. The identified gene arrangements are unique among metazoans, including each other, sharing no more than one or two single gene boundaries with a few distantly related taxa. Phylogenetic analysis of the amino acid sequences inferred from the sequenced genes confirms that the acoelomorph flatworms (acoels+nemertodermatids) do not belong to the Platyhelminthes, but are, instead, the most basal extant bilaterian group. Therefore, the Platyhelminthes, as traditionally constituted, is a polyphyletic phylum.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Codon / genetics
  • DNA, Mitochondrial / genetics*
  • Gene Order / genetics
  • Genome
  • Nucleic Acid Conformation
  • Phylogeny*
  • Platyhelminths / classification*
  • Platyhelminths / genetics
  • RNA, Transfer / genetics
  • Sequence Analysis, DNA
  • Sequence Analysis, Protein
  • Turbellaria / classification*
  • Turbellaria / genetics

Substances

  • Codon
  • DNA, Mitochondrial
  • RNA, Transfer