Invertebrate mtDNA Genetic Code [Code #5]
The Genetic Code for mtDNA of
Invertebrates is a messenger
RNA (mRNA)
code. Each of the 64 triplet codons in the table is
read 5' 
3'.
The table is organized such that the first letter in the
codon is read in the four rows at the left, the second
letter in the four columns across the top, and the third
letter as a line in each block of four. The code tables
uses the IUPAC single-letter abbreviations for
amino acids. Stop codons
are indicated in red or
as Stars (*).
The Invertebrate mtDNA code differs from the "Universal" as follows.
(1) UGA codes for Tryptophan (Trp, W) instead of a Stop Codon: UGR is two-fold degenerate for W.
(2) AGA and AGG (AGR) both code for Serine (Ser, S) instead of Arginine (Arg, R), such that AGN is four-fold degenerate for S.
(3) AUA as well as AUG code for Methionine (Met, M), such that AUR is two-fold degenerate for M.
(4) AUU and AUA and AUC (in the Honeybee genus Apis) can act as Start (Initiation) Codons instead of the conventional AUG.
This means that the first codon in an ORF may be Ile (I) instead of the expected M.
3'.
The table is organized such that the first letter in the
codon is read in the four rows at the left, the second
letter in the four columns across the top, and the third
letter as a line in each block of four. The code tables
uses the IUPAC single-letter abbreviations for
amino acids. Stop codons
are indicated in red or
as Stars (*). The Invertebrate mtDNA code differs from the "Universal" as follows.
(1) UGA codes for Tryptophan (Trp, W) instead of a Stop Codon: UGR is two-fold degenerate for W.
(2) AGA and AGG (AGR) both code for Serine (Ser, S) instead of Arginine (Arg, R), such that AGN is four-fold degenerate for S.
(3) AUA as well as AUG code for Methionine (Met, M), such that AUR is two-fold degenerate for M.
(4) AUU and AUA and AUC (in the Honeybee genus Apis) can act as Start (Initiation) Codons instead of the conventional AUG.
This means that the first codon in an ORF may be Ile (I) instead of the expected M.
Figure and text © 2024
by Steven M. Carr