中国汉族人mtDNA控制区异质性遗传规律

目的探讨中国汉族人mtDNA控制区异质性分布情况和遗传规律。方法将人mtDNA控制区扩增成6个部分互相重叠的片段,利用已建立的DHPLC技术分析其异质性规律。结果对150例汉族无关个体的多种组织检测,发现异质性个体的发生率达34%(51/150);个体的组织mtDNA异质性检出率最高为脑(50/150)、心肌(48/150)、最低为骨骼(22/150);本组共发现mtDNA控制区异质性位点有36个;同一个体可有多个异质性位点,最多的不超过3个;未发现异质性发生率有性别差异;超过41岁的高年龄组的异质性发生率(27/59)高于低年龄组(24/91);同一个体在2年前后取的血样,异质性检测结果一致;同一母系不同成员的异质性位点相同,但异质性mtDNA的含量有差异。结论DHPLC检测mtDNA控制区异质性具有高分辩力;mtDNA控制区异质性在中国汉族人中广泛存在;上述结果可作为mtDNA控制区多态性作个人认定和亲权鉴定的指导性资料。

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.