The genetic code in Saccharomyces cerevisiae mitochondrial DNA (mtDNA) differs from the universal code by TGA being read as tryptophan, CTN as threonine, ATA as methionine and CGN for arginine, with CGA and CGC absent, that is recognized as the “yeast mitochondrial code” (transl_table=3). Recently we completed mtDNAs for all Saccharomyces species. Detailed analysis of protein coding genes revealed differences from already established yeast mitochondrial code. GUG is used as the translation start in the S. cariocanus cox3 gene as well as in free-standing ORF1 from several species. Arginine CGA and CGC codons considered as unassigned are present in endonucleases coded by introns. Due to the alternative splicing of cox1I5β and cobI1α, AUA considered as an initiation codon is absent. Consequently, the “yeast mitochondrial code” should be updated accepting CGA and CGC as arginine codons and GTG as the alternative initiation codon.
Keywords: mtDNA; genetic code; GTG; Saccharomyces
This work was supported by grants from the Slovak Grant Agency of Science (VEGA 1/0048/16).
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