Phylogeny of the Kinetoplastida: Taxonomic Problems and Insights into the Evolution of Parasitism

• Published in: Memórias do Instituto Oswaldo Cruz Vol. 96; no. 3; pp. 397 - 402
• Main Authors: Maslov, D A, Podlipaev, S A, Lukes, J
• Format: Journal Article
• Language: English
• Published: Brazil Fundação Oswaldo Cruz, Fiocruz 01.04.2001; Instituto Oswaldo Cruz, Ministério da Saúde; Fundação Oswaldo Cruz (FIOCRUZ)
• Subjects: Animals; Biological Evolution; Bodonina; Kinetoplastida; Kinetoplastida - classification; Kinetoplastida - genetics; Kinetoplastida, Bodonina, Trypanosomatina, parasitism, phylogeny; parasitism; PARASITOLOGY; Phylogeny; rRNA 18S; TROPICAL MEDICINE; Trypanosoma; Trypanosomatina; Kinetoplastida; parasitism; phylogeny; Bodonina; Trypanosomatina
• ISSN: 1678-8060; 0074-0276; 0074-0276; 1678-8060
• DOI: 10.1590/S0074-02762001000300021

To further investigate phylogeny of kinetoplastid protozoa, the sequences of small subunit (18S) ribosomal RNA of nine bodonid isolates and ten isolates of insect trypanosomatids have been determined. The root of the kinetoplastid tree was attached to the branch of Bodo designis and/or Cruzella marina. The suborder Trypanosomatina appeared as a monophyletic group, while the suborder Bodonina was paraphyletic. Among bodonid lineages, parasitic organisms were intermingled with free-living ones, implying multiple transitions to parasitism and supporting the `vertebrate-first hypothesis'. The tree indicated that the genera Cryptobia and Bodo are artificial taxa. Separation of fish cryptobias and Trypanoplasma borreli as different genera was not supported. In trypanosomatids, the genera Leptomonas and Blastocrithidia were polyphyletic, similar to the genera Herpetomonas and Crithidia and in contrast to the monophyletic genera Trypanosoma and Phytomonas. This analysis has shown that the morphological classification of kinetoplastids does not in general reflect their genetic affinities and needs a revision.