Study of mtDNA analysis from mixed stains used by cloning techniques

线粒体DNA（mitochondrialDNA，mtDNA）具有链状结构，不同于核DNA，核DNA由同源染色体组成。线粒体DNA的PCR产物通常是由单一排列的起源产生的。当分析混合菌株时，很难对每种STR类型进行鉴定。然而，mtDNA的PCR产物很容易通过克隆技术区分。制备9份混合斑样品，其被来自两个或三个志愿者的唾液和/或血液污染，并从这些受试者中提取DNA。用序列分析法进行线粒体DNA分型，然后将PCR产物插入大肠杆菌。通过菌落PCR和测序扩增每个菌落中的克隆片段。结果表明，在分析初级PCR产物时，在电泳图中观察到多个峰位置。可以从克隆样品中区分和鉴定每个PCR产物。因此，线粒体DNA的克隆分析对于区分混合缎纹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.