Mitochondrial DNA polymorphism detected with the restriction enzymes BstNI and BclI in a French Canadian population.

The enzymes BstNI and BclI were used to detect various human mitochondrial DNA RFLPs in a sample of 104 unrelated French Canadians. These sequence variations were found in total white blood cell DNA probed with whole human mitochondrial DNA. With BstNI, 6 mitochondrial DNA restriction patterns (morphs) were identified. BstNI morphs 2-6 each differ from morph 1 by one single distinct restriction site gain or loss on the mitochondrial DNA molecule. Although BstNI morph 1 was found in most of the subjects (80%), each other morph was observed at a frequency of at least 3%. With the enzyme BclI, 4 different morphs were detected. Morphs 2-4 also result from different single restriction site alteration as compared with BclI morph 1. The morph 1 was clearly the most frequent (95%) while morphs 3 and 4 were present in only 1% of the subjects. These data indicate that the enzyme BstNI and, to a much lesser extent, the enzyme BclI detect mitochondrial DNA polymorphism in Caucasians. They are therefore of interest for population genetics studies.