Group II introns in Eubacteria and Archaea: ORF-less introns and new varieties

Dawn M. Simon, Nicholas A.C. Clarke, Bonnie A. McNeil, Ian Johnson, Davin Pantuso, Lixin Dai, Dinggeng Chai, Steven Zimmerly

Research output: Contribution to journalArticlepeer-review

69 Scopus citations


Group II introns are a major class of ribozymes found in bacteria, mitochondria, and plastids. Many introns contain reverse transcriptase open reading frames (ORFs) that confer mobility to the introns and allow them to persist as selfish DNAs. Here, we report an updated compilation of group II introns in Eubacteria and Archaea comprising 234 introns. One new phylogenetic class is identified, as well as several specialized lineages. In addition, we undertake a detailed search for ORF-less group II introns in bacterial genomes in order to find undiscovered introns that either entirely lack an ORF or encode a novel ORF. Unlike organellar group II introns, we find only a handful of ORF-less introns in bacteria, suggesting that if a substantial number exist, they must be divergent from known introns. Together, these results highlight the retroelement character of bacterial group II introns, and suggest that their long-term survival is dependent upon retromobility. Published by Cold Spring Harbor Laboratory Press.

Original languageEnglish (US)
Pages (from-to)1704-1713
Number of pages10
Issue number9
StatePublished - Sep 2008
Externally publishedYes


  • Evolution
  • Intron-encoded protein
  • Retroelement
  • Reverse transcriptase

ASJC Scopus subject areas

  • Molecular Biology


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