invertebrate mitochondrial code invertebrate mitochondrial code the invertebrate mitochondrial code (translation table 5) is a genetic code used by the mitochondrial genome of invertebrates. the code aas = ffllssssyy**ccwwllllpppphhqqrrrriimmttttnnkkssssvvvvaaaaddeegggg starts = ---m----------------------------mmmm---------------m------------ base1 = ttttttttttttttttccccccccccccccccaaaaaaaaaaaaaaaagggggggggggggggg base2 = ttttccccaaaaggggttttccccaaaaggggttttccccaaaaggggttttccccaaaagggg base3 = tcagtcagtcagtcagtcagtcagtcagtcagtcagtcagtcagtcagtcagtcagtcagtcag bases: adenine (a), cytosine (c), guanine (g) and thymine (t) or uracil (u). amino acids: alanine (ala, a), arginine (arg, r), asparagine (asn, n), aspartic acid (asp, d), cysteine (cys, c), glutamic acid (glu, e), glutamine (gln, q), glycine (gly, g), histidine (his, h), isoleucine (ile, i), leucine (leu, l), lysine (lys, k), methionine (met, m), phenylalanine (phe, f), proline (pro, p), serine (ser, s), threonine (thr, t), tryptophan (trp, w), tyrosine (tyr, y), valine (val, v). differences from the standard code dna codonsrna codonsthis code (5)standard code (1) agaagaser (s)arg (r) aggaggser (s)arg (r) ataauamet (m)ile (i) tgaugatrp (w)stop = ter (*) note: the codon agg is absent in drosophila. 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 (as in the pterobranchia mitochondrial code) or arginine (as in the standard genetic code). 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."