Journal of Molecular Evolution

, Volume 64, Issue 5, pp 591–600 | Cite as

Novel Group I Introns Encoding a Putative Homing Endonuclease in the Mitochondrial cox1 Gene of Scleractinian Corals

  • Hironobu Fukami
  • Chaolun Allen Chen
  • Chi-Yung Chiou
  • Nancy Knowlton


Analyses of mitochondrial sequences revealed the existence of a group I intron in the cytochrome oxidase subunit 1 (cox1) gene in 13 of 41 genera (20 out of 73 species) of corals conventionally assigned to the suborder Faviina. With one exception, phylogenies of the coral cox1 gene and its intron were concordant, suggesting at most two insertions and many subsequent losses. The coral introns were inferred to encode a putative homing endonuclease with a LAGLI-DADG motif as reported for the cox1 group I intron in the sea anemone Metridium senile. However, the coral and sea anemone cox1 group I introns differed in several aspects, such as the intron insertion site and sequence length. The coral cox1 introns most closely resemble the mitochondrial cox1 group I introns of a sponge species, which also has the same insertion site. The coral introns are also more similar to the introns of several fungal species than to that of the sea anemone (although the insertion site differs in the fungi). This suggests either a horizontal transfer between a sponge and a coral or independent transfers from a similar fungal donor (perhaps one with an identical insertion site that has not yet been discovered). The common occurrence of this intron in corals strengthens the evidence for an elevated abundance of group I introns in the mitochondria of anthozoans.


Scleractinia Corals Mitochondria Group I intron Homing endonuclease cox1 


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Copyright information

© Springer Science+Business Media, LLC 2007

Authors and Affiliations

  • Hironobu Fukami
    • 1
    • 4
  • Chaolun Allen Chen
    • 2
  • Chi-Yung Chiou
    • 2
  • Nancy Knowlton
    • 1
    • 3
  1. 1.Center for Marine Biodiversity and ConservationScripps Institution of Oceanography, University of California San DiegoLa JollaUSA
  2. 2.Research Centre for Biodiversity, Academia SinicaTaipeiTaiwan
  3. 3.Smithsonian Tropical Research InstitutePanamaRepública de Panamá
  4. 4.Seto Marine Biological Laboratory, Field Science Education and Research Center, Kyoto UniversityWakayamaJapan

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