Affiliation: | DONG Jiuhong1,2,WEN Jianfan1,XIN Dedong1,2 & LU Siqi3 1.Lab of Cellular and Molecular Evolution,Kunming Institution of Zoology,Chinese Academy of Sciences,Kunming 650223,China;2.Graduate school of Chinese Academy of Science,Beijing 100039,China;3.Capital University of Medical Sciences,Beijing 100054,China |
Abstract: | In addition to its medical importance as parasitic pathogen, Entamoeba has aroused people’s interest in its evolutionary status for a long time. Lacking mitochondrion and other intracellular organelles common to typical eukaryotes, Entamoeba and several other amitochondrial protozoans have been recognized as ancient pre-mitochondriate eukaryotes and named “archezoa”, the most primitive extant eukaryotes. It was suggested that they might be living fossils that remained in a primitive stage of evolution before acquisition of organelles, lying close to the transition between prokaryotes and eukaryotes. However, recent studies revealed that Entamoeba contained an organelle, “crypton” or “mitosome”, which was regarded as specialized or reductive mitochondrion. Relative molecular phylogenetic analyses also indicated the existence or the probable existence of mitochondrion in Entamoeba. Our phylogenetic analysis based on DNA topoisomerase II strongly suggested its divergence after some mitchondriate eukaryotes. Here, all these recent researches are reviewed and the evolutionary status of Entamoeba is discussed. |