Directed Mutations Recode Mitochondrial Genes: From Regular to Stopless Genetic Codes

Mitochondrial genetic codes evolve as side effects of stop codon ambiguity: suppressor tRNAs with anticodons translating stops transform genetic codes to stopless genetic codes. This produces peptides from frames other than regular ORFs, potentially increasing protein numbers coded by single sequences. Previous descriptions of marine turtle Olive Ridley mitogenomes imply directed stop-depletion of noncoding +1 gene frames, stop-creation recodes regular ORFs to stopless genetic codes. In this analysis, directed stop codon depletion in usually noncoding gene frames of the spiraling whitefly Aleurodicus dispersusʼ mitogenome produces new ORFs, introduces stops in regular ORFs, and apparently increases coding redundancy between different gene frames. Directed stop codon mutations switch between peptides coded by regular and stopless genetic codes. This process seems opposite to directed stop creation in HIV ORFs within genomes of immunized elite HIV controllers. Unknown DNA replication/edition mechanisms probably direct stop creation/depletion beyond natural selection on stops. Switches between genetic codes regulate translation of different gene frames