Exploring of rare differences in mtGenomes between MZ twins using massively parallel sequencing

Compared with nuclear DNA, fewer DNA repair mechanisms in mitochondria and lack of proofreading capabilities in the mtDNA polymerase help introduce more variability between MZ twins. In our previous study, we used ultra-deep mtGenome sequencing to characterize point heteroplasmy and nucleotide variant in blood samples of MZ twins. In the present study, we characterize minor differences of mtGenomes in saliva and hair shaft samples from six sets of MZ twins using the Precision ID mtDNA Whole Genome Panel, Ion S5 XL system, and Converge Software. Additionally, the effectiveness of different tissue samples for differentiating between MZ twins was evaluated. Point heteroplasmies were observed in all sets of MZ twins regardless of sample type. Overall, more variants were observed in the mtGenome from hair shaft samples than that from blood and saliva samples. The results of this study further support that the mtGenome analysis could be used to distinguish MZ twins from each other.