Figure 1.

Clonal analysis of CO1 and CO2 genes from a typical AD patient showing sites of heteroplasmic mutations in mtDNA. mtDNA was prepared and cloned into appropriate vectors as described. Ten independent clones of each gene were subjected to automated sequencing. Five missense mutations and one silent mutation are represented. Black boxes indicate sites of point mutations. Open boxes indicate sites of wild-type bases. As can be seen, 50% of the clones for the CO1 gene contained a least one point mutation, whereas 30% of the clones for the CO2 gene contained at least one mutation. In most instances, these mutations appear together in the same clone suggesting a unique mutated mitochondrial genome.