Extensive rearrangements in the mitochondrial DNA in somatic hybrids of Nicotiana tabacum and Nicotiana knightiana

Summary Mitochondrial DNA (mtDNA) was studied in the leaves of Nicotiana tabacum+Nicotiana knightiana somatic hybrids previously described. Restriction patterns generated by the SalI and BamHI restriction endonucleases were different from both parents in the eight hybrids, and made up of parental and non-parental fragments. Rearrangements in the mtDNAs have been confirmed by DNA-DNA hybridization using, as a probe, labelled 2/12 plasmid DNA which contains the E. coli 16S and 23S rRNA genes. Novel patterns can be explained by new combinations of unaltered parental mtDNA molecules, and by genetic recombination.