Evidence that eukaryotes and eocyte prokaryotes are immediate relatives.
The phylogenetic origin of eukaryotes has been unclear because eukaryotic nuclear genes have diverged substantially from prokaryotic ones. The genes coding for elongation factor EF-1 alpha were compared among various organisms. The EF-1 alpha sequences of eukaryotes contained an 11-amino acid segment that was also found in eocytes (extremely thermophilic, sulfur-metabolizing bacteria) but that was absent in all other bacteria. The related (paralogous) genes encoding elongation factor EF-2 and initiation factor IF-2 also lacked the 11-amino acid insert. These data imply that the eocytes are the closest surviving relatives (sister taxon) of the eukaryotes.
Rivera
M C
MC
Molecular Biology Institute, University of California, Los Angeles 90024.
Lake
J A
JA
D000595:Amino Acid Sequence; D001419:Bacteria / Q000235:genetics*; D001483:Base Sequence; D005075:Biological Evolution; D004269:DNA, Bacterial / Q000235:genetics; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D020648:Peptide Elongation Factor 1; D020653:Peptide Elongation Factor G; D010444:Peptide Elongation Factor Tu / Q000737:chemistry / Q000235:genetics*; D010445:Peptide Elongation Factors / Q000235:genetics*; D010448:Peptide Initiation Factors / Q000235:genetics*; D010802:Phylogeny; D010944:Plants / Q000235:genetics; D039881:Prokaryotic Initiation Factor-2; D011487:Protein Conformation; D012441:Saccharomyces cerevisiae / Q000235:genetics; D012689:Sequence Homology, Nucleic Acid
D004269:DNA, Bacterial; D020648:Peptide Elongation Factor 1; D020653:Peptide Elongation Factor G; D010445:Peptide Elongation Factors; D010448:Peptide Initiation Factors; D039881:Prokaryotic Initiation Factor-2; D010444:Peptide Elongation Factor Tu