Phylogenetic place of mitochondrion-lacking protozoan, Giardia lamblia, inferred from amino acid sequences of elongation factor 2

Mol Biol Evol. 1995 Sep;12(5):782-93. doi: 10.1093/oxfordjournals.molbev.a040256.


Partial regions of the mRNA encoding a major part of translation elongation factor 2 (EF-2) from a mitochondrion-lacking protozoan, Giardia lamblia, were amplified by polymerase chain reaction, and their primary structures were analyzed. The deduced amino acid sequence was aligned with other eukaryotic and archaebacterial EF-2's, and the phylogenetic relationships among eukaryotes were inferred by the maximum likelihood (ML) and the maximum parsimony (MP) methods. The ML analyses using six different models of amino acid substitutions and the MP analysis consistently suggest that among eukaryotic species being analyzed, G. lamblia is likely to have diverged from other higher eukaryotes on the early phase of eukaryotic evolution.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Archaea / classification
  • Archaea / genetics
  • Base Sequence
  • Blotting, Southern
  • Cloning, Molecular
  • DNA Primers
  • DNA, Protozoan / chemistry
  • DNA, Protozoan / isolation & purification
  • Escherichia coli
  • Giardia lamblia / classification
  • Giardia lamblia / genetics*
  • Humans
  • Mitochondria
  • Molecular Sequence Data
  • Peptide Elongation Factor 2
  • Peptide Elongation Factors / biosynthesis
  • Peptide Elongation Factors / chemistry
  • Peptide Elongation Factors / genetics*
  • Phylogeny*
  • Polymerase Chain Reaction
  • RNA, Messenger / analysis
  • RNA, Messenger / biosynthesis
  • Sequence Homology, Amino Acid


  • DNA Primers
  • DNA, Protozoan
  • Peptide Elongation Factor 2
  • Peptide Elongation Factors
  • RNA, Messenger

Associated data

  • GENBANK/D29835