title: Microsporidia are related to Fungi: evidence from the largest subunit of RNA polymerase II and other proteins.
abstract: We have determined complete gene sequences encoding the largest subunit of the RNA polymerase II (RBP1) from two Microsporidia, Vairimorpha necatrix and Nosema locustae. Phylogenetic analyses of these and other RPB1 sequences strongly support the notion that Microsporidia are not early-diverging eukaryotes but instead are specifically related to Fungi. Our reexamination of elongation factors EF-1alpha and EF-2 sequence data that had previously been taken as support for an early (Archezoan) divergence of these amitochondriate protists show such support to be weak and likely caused by artifacts in phylogenetic analyses. These EF data sets are, in fact, not inconsistent with a Microsporidia + Fungi relationship. In addition, we show that none of these proteins strongly support a deep divergence of Parabasalia and Metamonada, the other amitochondriate protist groups currently thought to compose early branches. Thus, the phylogenetic placement among eukaryotes for these protist taxa is in need of further critical examination.
authors.affiliation: Department of Zoology, The Natural History Museum, London SW7 5BD, United Kingdom.
authors.forename: R P
authors.initials: RP
authors.lastname: Hirt
authors.forename: J M
authors.initials: JM
authors.lastname: Logsdon
authors.forename: B
authors.initials: B
authors.lastname: Healy
authors.forename: M W
authors.initials: MW
authors.lastname: Dorey
authors.forename: W F
authors.initials: WF
authors.lastname: Doolittle
authors.forename: T M
authors.initials: TM
authors.lastname: Embley
mesh_terms: D000818:Animals; D017931:DNA Primers / Q000235:genetics; D005057:Eukaryotic Cells / Q000145:classification; D005658:Fungi / Q000235:genetics*; D005872:Giardia / Q000235:genetics; D016816:Microsporida / Q000235:genetics*; D008969:Molecular Sequence Data; D020648:Peptide Elongation Factor 1; D010445:Peptide Elongation Factors / Q000235:genetics; D010802:Phylogeny; D012319:RNA Polymerase II / Q000235:genetics*; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D014244:Trichomonas / Q000235:genetics
chemical_list: D017931:DNA Primers; D020648:Peptide Elongation Factor 1; D010445:Peptide Elongation Factors; D012319:RNA Polymerase II