Genetics of heteroplasmy in the mtDNA control region among the Chinese Han population

Objective To explore the distribution and genetic pattern of heteroplasmy of mtDNA control region among Chinese Han population. Methods The human mtDNA control region was amplified into 6 amplicons overlapped partially each other. Then these amplicons were analyzed by DHPLC which we developed to detect low heteroplasmic signals. Results There were 51 heteroplasmic cases(34%) found from different tissues of 150 unrelated individuals of the Chinese Han population. mtDNA heteroplasmy shows non-uniform distribution in various tissues. The highest occurrence of heteroplasmy was in brain tissues (50/150) and myocardium(48/150), the lowest was in bone tissues (22/150). 36 sites of heteroplasmy were identified in our samples. Three sites of mtDNA heteroplasmy rarely co-existed in one individual. No sex differences were detected in the frequency of mtDNA heteroplasmy. No change in the mtDNA heteroplasmy profile was detected of blood samples from the same individuals within 2 years. Individuals older than 41 years showed a heteroplasmy frequency significantly higher than their younger counterparts. Members from the same maternal pedigree in a family can share the same sites of mtDNA heteroplasmy but may have different heteroplasmy contents at those sites. Conclusion DHPLC is a highly sensitive technique in detecting heteroplasmy. mtDNA heteroplasmy widely exists in the Chinese Han population. The results shown here could potentially have a guidable value in forensic individual identification and parentage testing.