title: The analysis of 100 genes supports the grouping of three highly divergent amoebae: Dictyostelium, Entamoeba, and Mastigamoeba.
abstract: The phylogenetic relationships of amoebae are poorly resolved. To address this difficult question, we have sequenced 1,280 expressed sequence tags from Mastigamoeba balamuthi and assembled a large data set containing 123 genes for representatives of three phenotypically highly divergent major amoeboid lineages: Pelobionta, Entamoebidae, and Mycetozoa. Phylogenetic reconstruction was performed on approximately 25,000 aa positions for 30 species by using maximum-likelihood approaches. All well-established eukaryotic groups were recovered with high statistical support, validating our approach. Interestingly, the three amoeboid lineages strongly clustered together in agreement with the Conosa hypothesis [as defined by T. Cavalier-Smith (1998) Biol. Rev. Cambridge Philos. Soc. 73, 203-266]. Two amitochondriate amoebae, the free-living Mastigamoeba and the human parasite Entamoeba, formed a significant sister group to the exclusion of the mycetozoan Dictyostelium. This result suggested that a part of the reductive process in the evolution of Entamoeba (e.g., loss of typical mitochondria) occurred in its free-living ancestors. Applying this inexpensive expressed sequence tag approach to many other lineages will surely improve our understanding of eukaryotic evolution.
authors.affiliation: Unité Mixte de Recherche 7622 Centre National de la Recherche Scientifique, Université Paris 6, 9 Quai Saint Bernard, Bât C, 75005 Paris, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Bapteste
authors.forename: Henner
authors.initials: H
authors.lastname: Brinkmann
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Lee
authors.forename: Dorothy V
authors.initials: DV
authors.lastname: Moore
authors.forename: Christoph W
authors.initials: CW
authors.lastname: Sensen
authors.forename: Paul
authors.initials: P
authors.lastname: Gordon
authors.forename: Laure
authors.initials: L
authors.lastname: Duruflé
authors.forename: Terry
authors.initials: T
authors.lastname: Gaasterland
authors.forename: Philippe
authors.initials: P
authors.lastname: Lopez
authors.forename: Miklós
authors.initials: M
authors.lastname: Müller
authors.forename: Hervé
authors.initials: H
authors.lastname: Philippe
mesh_terms: D000656:Amoeba / Q000145:classification* / Q000235:genetics; D000818:Animals; D005075:Biological Evolution; D004023:Dictyostelium / Q000145:classification* / Q000235:genetics; D004747:Entamoeba / Q000145:classification* / Q000235:genetics; D005796:Genes; D006801:Humans; D008969:Molecular Sequence Data; D010802:Phylogeny