Sudy on the heteroplasmic substitutions in the mitochondrial DNA control region

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Detection of mitochondrial DNA variation is commonly carried out in Forensic Science. The control region of mtDNA is highly polymorphic and useful for individual identification purposes.Alternative strategies to DNA sequencing have been proposed for the detection of mutation. For the screening of mtDNA heteroplasmy, SSCP may be the most utilized method. This method is based on the different conformations which single stranded DNA adopts. Our results with 100 unrelated individuals showed that using this method one individual has differents patterns.We described three methods for extracting DNA from hair shafts, including the Phenol / Chloroform method, the NaI treatment method, and the Silica - beads method. With the degraded sample, amplification from the template by the Phenol / Chloroform method produced no results. In contrast, high fluorescent peak heights adequate for sequencing mtDNA were obtained from our two methods, confirming that the NaI treatment and Silica - beads methods are volid, reliable means of extracting and amplifying mtDNA from hair shafts.The sequences of the HV1 and HV2 regions from close maternal relatives (mother - child pairs) were compared to determine the frequency of heteroplasmic mutations. A total of 16 blood and hair samples were sequenced. The several heteroplasmic point mutations were found in mother and child samples.