Codons AGA and AGG are read as glycine in ascidian mitochondria

J Mol Evol. 1993 Jan;36(1):1-8. doi: 10.1007/BF02407301.


A 1.2-kb DNA fragment of the cytochrome oxidase subunit I (CO I) gene of mitochondria isolated from an ascidian, Halocynthia roretzi, was amplified by polymerase chain reaction (PCR) and sequenced. Codons AGA and AGG appeared in its reading frame, indicating that these are sense codons in this organelle. Sequence comparisons with the corresponding regions of other animal mitochondrial CO I genes suggest that codons AGA and AGG correspond to glycine in the ascidian mitochondrial genome, but not to serine as in most invertebrate genomes, nor to stops as in vertebrate genomes. The other codons are identical to those of vertebrate mitochondria.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Codon / genetics*
  • DNA, Mitochondrial / genetics
  • Electron Transport Complex IV / genetics*
  • Glycine / chemistry
  • Glycine / genetics*
  • Mitochondria / enzymology*
  • Molecular Sequence Data
  • Peptide Fragments
  • Polymerase Chain Reaction
  • Urochordata / genetics*


  • Codon
  • DNA, Mitochondrial
  • Peptide Fragments
  • Electron Transport Complex IV
  • Glycine