Sequence Polymorphisms of the Control Region of Human Mitochondrial DNA in Japanese Population

Nucleotide sequences of 2 hypervariable regions (HV1, HV2) within the control region of human mitochondrial DNA (mtDNA) were analyzed from 55 unrelated Japanese. About 700 nucleotides were sequenced by using the nested PCR and the solid-phase direct sequencing methods. Comparison of these sequences with Anderson's reference sequence revealed 97 mutation types within 93 positions, and 11 positions of them were novel. Fifty five samples analyzed were classified into 52 different sequences, while 3 pairs have shown the same sequences. Comparison of the Japanese sequences to those reported from other populations indicated many differences in such a point that the substitutions at 16,223 and 73 in Japanese were more frequent than those in Caucasian, while the substitutions at 16,126 and 16,311 in Japanese were less frequent than those in Caucasian. Twenty one of 55 samples analyzed showed a T-to-C transition at the position 16,189 of the C-stretch region in the HV1 region. This replacement caused the blurred bands on the sequence image, which resulted in the ambiguity of exact number of cytosine in the C-stretch region of HV1. For this ambiguity, the number of cytosine in the C-stretch region should not be currently taken into account in forensic practices of individualization of evidence samples. Regardless of such problem, the polymorphisms of HV1 and HV2 regions are highly useful for individual identification.