Application of internal reference method in identification of mitochondrial DNA purity.

In this study,the genes β-Actin,RabcL and COXIII were used as the internal reference markers to detect the purity of mitochondrial DNA extracted using differential centrifugation through polymerase chain reaction(PCR) and agarose gel electrophoresis.The result showed that mitochondrial DNA extracted using differential centrifugation contained impurities,which included nuclear and chloroplast DNA(ctDNA).Then the mtDNA was diluted and the purity of the diluted mtDNA was detected using the same method.It was found that the nuclear DNA became undetectable by PCR when the mtDNA was diluted 300-400 times.However,the mtDNA and ctDNA could still be amplified by PCR.The mtDNA obtained in this way could be used as mtDNA without contamination of nuclear DNA.