Human mitochondrial genome and the evolution of methionine transfer ribonucleic acids.

The recently deciphered sequence of the human mitochondrial genome is analyzed in the light of an archigenetic hypothesis, according to which mitochondria are derived neither from pro- nor eukaryotes but from more primitive organisms. The possibility that animal mitochondria have only one gene both for elongator and initiator methionine tRNA is supported but C-A pair forming cytosine in the anticodon of these tRNAs is considered to be unmodified. The evolution of the gene and of the codon reading pattern of methionine tRNA is discussed.