The potato mitochondrial initiator methionine tRNA gene and its flanking regions: an illustration of the diversity of mitochondrial genome rearrangements among plant species

The initiator methionine transfer RNA (tRNA fMet) gene was identified on a 347 bp Eco RI-Hind III DNA fragment of the potato mitochondrial (mt) genome. The sequence of this gene shows 1 to 7 nucleotide differences with the other plant mt tRNAs fMet or tRNA fMet genes studied so far. Whereas the tRNA fMet gene is present as a single copy in the potato mt genome, a tRNA 'pseudogene' corresponding to 60% of a complete tRNA (from the 5′ end to the variable region) and located at 105 nucleotides upstream of the tRNA fMet gene on the opposite strand was shown to be repeated at least three times. Furthermore, the physical environment of the tRNA fMet gene in the mt genome is very different among plants, which suggests that the tRNA fMet gene region has often been implicated in recombination events of plant mt genomes leading to important rearrangements in gene order. © 1993 Kluwer Academic Publishers.