Mitochondrial genome data support the basal position of Acoelomorpha and the polyphyly of the Platyhelminthes.
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.
Ruiz-Trillo
Iñaki
I
Departament de Genètica, Universitat de Barcelona, Av. Diagonal, 645, 08028 Barcelona, Spain.
Riutort
Marta
M
Fourcade
H Matthew
HM
Baguñà
Jaume
J
Boore
Jeffrey L
JL
D000818:Animals; D003062:Codon / Q000235:genetics; D004272:DNA, Mitochondrial / Q000235:genetics*; D023061:Gene Order / Q000235:genetics; D016678:Genome; D009690:Nucleic Acid Conformation; D010802:Phylogeny; D010986:Platyhelminths / Q000145:classification* / Q000235:genetics; D012343:RNA, Transfer / Q000235:genetics; D017422:Sequence Analysis, DNA; D020539:Sequence Analysis, Protein; D014419:Turbellaria / Q000145:classification* / Q000235:genetics
D003062:Codon; D004272:DNA, Mitochondrial; D012343:RNA, Transfer