- Autor(in)
- Seitenbereich
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059 - 069
- Zusammenfsg.
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A maximum likelihood analysis of the amino acid sequences of the largest subunit of the DNA-dependent RNA polymerase III suggests that Giardia lamblia, a protozoan organism lacking mitochondria. had not diverged from the line leading to higher eukaryotes before endo symbiosis of proto-mitochondria occurred. This is in accordance with the suggestion of Lanzendorfer et al.(1) from parsimony and distance method analyses of the same data. but in disagreement with the suggestion of a tree of small subunit ribosomal RNAs (2,3,4). Since the small subunit ribosomal RNA of G. lamblia is extremely high in G+C content, we suggest that the tree inferred from amino acid sequences is more reliable than that of ribosomal RNAs. This study, as well as our previous study (5), suggests that phylogenetic trees inferred from ribosomal RNAs should be reexamined using amino acid sequences of proteins particularly when G+C content differs among lineages.