Ancient gene duplication and differential gene flow in plastid lineages: the GroEL/Cpn60 example

J Mol Evol. 1999 Jan;48(1):112-7. doi: 10.1007/pl00006438.


Cryptomonads, small biflagellate algae, contain four different genomes. In addition to the nucleus, mitochondrion, and chloroplast is a fourth DNA-containing organelle the nucleomorph. Nucleomorphs result from the successive reduction of the nucleus of an engulfed phototrophic eukaryotic endosymbiont by a secondary eukaryotic host cell. By sequencing the chloroplast genome and the nucleomorph chromosomes, we identified a groEL homologue in the genome of the chloroplast and a related cpn60 in one of the nucleomorph chromosomes. The nucleomorph-encoded Cpn60 and the chloroplast-encoded GroEL correspond in each case to one of the two divergent GroEL homologues in the cyanobacterium Synechocystis sp. PCC6803. The coexistence of divergent groEL/cpn60 genes in different genomes in one cell offers insights into gene transfer from evolving chloroplasts to cell nuclei and convergent gene evolution in chlorophyll a/b versus chlorophyll a/c/phycobilin eukaryotic lineages.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Chaperonin 60 / genetics*
  • Chloroplasts / genetics
  • Eukaryota / classification
  • Eukaryota / genetics
  • Evolution, Molecular
  • Gene Duplication*
  • Genes, Plant / genetics*
  • Molecular Sequence Data
  • Phylogeny
  • Plant Proteins / genetics
  • Plastids / genetics*
  • Sequence Homology, Amino Acid


  • Chaperonin 60
  • Plant Proteins

Associated data

  • GENBANK/AJ010647