Study of mtDNA analysis from mixed stains used by cloning techniques

线粒体DNA(MtDNA)具有链状结构，不同于由同源染色体组成的核DNA。线粒体DNA的聚合酶链式反应产物与线粒体DNA一样，通常是由单一排列的起源产生的。在分析混合菌斑时，很难识别每种STR类型。然而，利用克隆技术可以很容易地区分mtDNA的PCR产物。取2名或3名志愿者唾液和/或血液污染的混合污渍标本9份，提取DNA。常规的mtDNA分型是通过序列分析进行的，然后将PCR产物插入到E.Coli中。通过菌落聚合酶链式反应和测序，在每个菌落中扩增出一个克隆片段。结果表明，对初级聚合酶链式反应产物进行分析时，在电泳图上观察到多峰位置。可以从克隆样本中区分和鉴定每个PCR产物。因此，线粒体DNA的克隆分析对于区分混合绸缎样品和鉴定个体是非常有用的。

Mitochondrial DNA(mtDNA) has a chain structure, and it is different from nuclear DNA which consists of homologous chromosomes. The PCR product of mtDNA is usually produced by the origin for the single arrangement as for the mtDNA. When analyzing mixed stains, it is difficult to identify for each STR types. However, PCR products of mtDNA are easily distinguishable by using cloning techniques. 9 samples of mixed stain, which are contaminated by saliva and/or blood from two or three volunteer, are prepared and DNA is extracted from these subjects. Usual mtDNA typing has done by sequence analysis, and then PCR products are inserted into E.Coli. A cloning segment in each colony is amplified by colony-PCR and sequencing. As results, multiple peak location is observed in the electoropherogram when analyzed primary PCR products. It is possible to distinguish and identify in each PCR product from cloning samples. Therefore, cloning analysis of mtDNA is very useful for distinguishing mixed satin samples and identifying individuals.