Gene gain and gene loss in streptococcus: is it driven by habitat?

Mol Biol Evol. 2006 Dec;23(12):2379-91. doi: 10.1093/molbev/msl115. Epub 2006 Sep 11.


Bacterial genomes can evolve either by gene gain, gene loss, mutating existing genes, and/or by duplication of existing genes. Recent studies have clearly demonstrated that the acquisition of new genes by lateral gene transfer (LGT) is a predominant force in bacterial evolution. To better understand the significance of LGT, we employed a comparative genomics approach to model species-specific and intraspecies gene insertions/deletions (ins/del among 12 sequenced streptococcal genomes using a maximum likelihood method. This study indicates that the rate of gene ins/del is higher on the external branches and varies dramatically for each species. We have analyzed here some of the experimentally characterized species-specific genes that have been acquired by LGT and conclude that at least a portion of these genes have a role in adaptation.

Publication types

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

MeSH terms

  • Adaptation, Biological
  • Ecosystem*
  • Evolution, Molecular
  • Gene Duplication*
  • Gene Transfer, Horizontal / physiology
  • Genes, Bacterial / physiology
  • Genome, Bacterial
  • Loss of Heterozygosity / physiology*
  • Models, Molecular
  • Mutagenesis, Insertional
  • Phylogeny
  • Protein Conformation
  • Species Specificity
  • Streptococcus / classification
  • Streptococcus / genetics*
  • Streptococcus agalactiae / genetics
  • Streptococcus mutans / genetics
  • Streptococcus pneumoniae / genetics
  • Streptococcus pyogenes / genetics
  • Streptococcus thermophilus / genetics