Abstract: Objective To analyze and detect the whole genome sequence of human mitochondrial DNA （mtDNA） by Ion Torrent PGMTM platform and to study the differences of mtDNA sequence in different tissues. Methods Samples were collected from 6 unrelated individuals by forensic postmortem examination, including chest blood, hair, costicartilage, nail, skeletal muscle and oral epithelium. Amplification of whole genome sequence of mtDNA was performed by 4 pairs of primer. Libraries were constructed with Ion ShearTM Plus Reagents kit and Ion Plus Fragment Library kit. Whole genome sequencing of mtDNA was performed using Ion Torrent PGMTM platform. Sanger sequencing was used to determine the heteroplasmy positions and the mutation positions on HVⅠ region. Results The whole genome sequence of mtDNA from all samples were amplified successfully. Six unrelated individuals belonged to 6 different haplotypes. Different tissues in one individual had heteroplasmy difference. The heteroplasmy positions and the mutation positions on HVⅠ region were verified by Sanger sequencing. After a consistency check by the Kappa method, it was found that the results of mtDNA sequence had a high consistency in different tissues. Conclusion The testing method used in present study for sequencing the whole genome sequence of human mtDNA can detect the heteroplasmy difference in different tissues, which have good consistency. The results provide guidance for the further applications of mtDNA in forensic science.

Key words: forensic genetics, DNA, mitochondrial, genetic heterogeneity, Ion Torrent PGMTM sequencing system, high-throughput nucleotide sequencing