mtDNA was amplified using 1 ng total DNA and long-range proofreading PCR (TaKaRa LR DNA Polymerase) with primers specific for the mitochondrial genome (Supplemental Table 1). 500 pg of mtDNA amplicon per sample were used for sequencing library preparation with Nextera XT reagents (Illumina) similar to previously described (Masser et al. 2013 (link)). Libraries were diluted to 4 nM and pooled for benchtop next generation sequencing (MiSeq, Illumina) using 600 cycle (2x250bp) reagents (Illumina) at a final library concentration of 12 pM. Detailed bioinformatics analysis methods are provided in the Supplemental Methods.