The vertebrate mitochondrial code (translation table 2) is the genetic code found in the mitochondria of all vertebrata.
AGA and AGG were thought to have become mitochondrial stop codons early in vertebrate evolution.
[1] However, at least in humans it has now been shown that AGA and AGG sequences are not recognized as termination codons.
A -1 mitoribosome frameshift occurs at the AGA and AGG codons predicted to terminate the CO1 and ND6 open reading frames (ORFs), and consequently both ORFs terminate in the standard UAG codon.
[2] Mitochondrial genes in some vertebrates (including humans) have incomplete stop codons ending in U or UA, which become complete termination codons (UAA) upon subsequent polyadenylation.