The molecular basis of genetic diversity among cytoplasms of Triticum and Aegilops : 5. Mitochondrial genome diversity among Aegilops species having identical chloroplast genomes.

Restriction fragment patterns of mtDNA isolated from the cytoplasm of three groups of Aegilops species (or accessions) which are known to carry the identical chloroplast genome but distinctly different cytoplasmic genomes (plasmons) have been analysed using five restriction endonucleases. Two to four different mitochondrial genomes are found in each group, between which the percent common restriction fragments amounts to 86-97%, whereas the same parameter obtained between mitochondrial genomes of the different groups ranges from 34 to 42%. Mitochondrial genome diversity is far more extensive than the chloroplast genome diversity, and the former provides a useful key for the phylogenetic relationships between cytoplasms of closely related species or even different accessions of the same species. The mitochondrial and chloroplast genome differentiation most certainly accounts for the plasmon variability known in this genus.