用PCR和ESI-TOF-MS技术检测线粒体DNA的异质性

目的用PCR和ESI-TOF-MS分型技术检测线粒体DNA（mtDNA）D环高变区,通过碱基组成分析mtDNA的异质性。方法从华东汉族群体选取12名无关个体,用PLEX-ID平台进行mtDNA分型。该平台使用12对引物,对mtDNA高变区1（HVⅠ,引物所跨区域为15893~16451）进行碱基组成分析;使用另外12对引物,对mtDNA高变区2（HVⅡ,引物所跨区域为5~603）进行碱基组成分析,考察mtDNA异质性频率。结果 mtDNA多态性区域的碱基组成信息反映出区段内有无异质性。在高变区Ⅰ的12个区段中,有3个区段表现出多聚C长度异质性：在mtDNA高变区Ⅱ（31~576）的12个区段中,有3个区段检见点异质性,另外5个区域检见Poly C长度异质性。结论群体调查表明,mtDNA的序列异质性多见于高变区Ⅱ的103~267区段,多聚C长度异质性多见于高变区Ⅰ的16124~16201、16157~16201、16182~16250区段和高变区Ⅱ的234~367、431~576区段。将mtDNA标记用于母系关系检验和（或）个体识别时,需要格外留意这些异质性信息,以免结论错误。

Detection of Mitochondrial DNA Heteroplasmy by PCR and ESI-TOF-MS

Objective To test the hyper-variable regions of D-loop of mitochondrial DNA by a genotyping method based on PCR and ESI-TOF-MS technology in order to analyze the mitochondrial DNA heteroplasmy in Han individuals. Method mtDNA of 12 individuals from Han population in eastern China were genotyped by PLEX-ID platform. Base compositions of 12 amplicons in hyper-variable region 1 （HV I） derived from primers covering coordinates 15924-16428 and those of another 12 amplicons in hyper-variable region 2 （HV II） derived from primers covering coordinates 31-576 were determined. The rate of mitoehon- drial DNA heteroplasmy was investigated. Results According to the base compositions, 3 segments in HV I and 5 segments in HV II were found to be poly C length heteroplasmic, and another 3 segments in HV II were point heteroplasmic. Conclusion Sequence heteroplasmy is easily found in HV II nt103-267. Poly C length heteroplasmy is found at regions of nt 16124-16201, nt 16182-16250 in HV I and regions of nt 234-367, nt 431-576 in HV II. To prevent wrong conclusions, attentions should be paid to heteroplasmy when mtDNA is applied for maternal testing and individual identification.