Intramolecular recombination of a mitochondrial minicircular plasmid-like DNA of date-palm mediated by a set of short direct-repeat sequences.

A molecular clone containing the complete sequence of a mitochondrial circular plasmid-like DNA (the R plasmid) isolated from the date-palm variety V3DP was used as a probe in Southern analyses of mitochondrial DNA prepared from other varieties. Another circular structure (the S plasmid) was detected in some of these varieties, and sequenced from variety V2DP. It appears that the R plasmid could have arisen from the S plasmid by an intermolecular recombination event at a set of 26-bp imperfect short direct repeats.