Distinguishing mitochondrial DNA and NUMT sequences amplified with the precision ID mtDNA whole genome panel

Nuclear mitochondrial DNA segments (NUMTs) are generated via transfer of portions of the mitochondrial genome into the nuclear genome. Given their common origin, there is the possibility that both the mitochondrial and NUMT segments may co-amplify using the same set of primers. Thus, analysis of the variation of the mitochondrial genome must take into account this co-amplification of mitochondrial and NUMT sequences. The study herein builds on data from the study by Strobl et al. (Strobl et al., 2019), in which multiple point heteroplasmies were called with an “N” to prevent labeling NUMT sequences mimicking mitochondrial heteroplasmy and being interpreted as true mitochondrial in origin sequence variants. Each of these point heteroplasmies was studied in greater detail, both molecularly and bioinformatically, to determine whether NUMT or true mitochondrial DNA variation was present. The bioinformatic and molecular tools available to help distinguish between NUMT and mitochondrial DNA and the effect of NUMT sequences on interpretation were discussed.