Invertebrate mitochondrial code

The code

Differences from the standard code

Alternative initiation codons

• AUA, AUU
• AUC: Apis
• GUG: Polyplacophora
• UUG: Ascaris, Caenorhabditis.

  Systematic range

• Nematoda: Ascaris, Caenorhabditis ;
• Mollusca: Bivalvia); Polyplacophora;
• Arthropoda/Crustacea: Artemia;
• Arthropoda/Insecta: Drosophila .

  Other variations

• Several arthropods translate the codon AGG as lysine instead of serine or arginine.
• GUG may possibly function as an initiator in Drosophila. AUU is not used as an initiator in Mytilus
• "An exceptional mechanism must operate for initiation of translation of the cytochrome oxidase subunit I mRNA in both D. melanogaster and D. yakuba, since its only plausible initiation codon, AUA, is out of frame with the rest of the gene. Initiation appears to require the "reading" of an AUAA quadruplet, which would be equivalent to initiation at AUA followed immediately by a specific ribosomal frameshift. Another possible mechanism... is that the mRNA is "edited" to bring the AUA initiation into frame."