mtDNA sequence variation pattern in single-cell populations from patients with leukemia and healthy controls. (A) The number of mtDNA haplotypes (including the aggregate haplotype and the nonaggregate haplotypes that differ from aggregate sequence by nucleotide substitutions or indels or both) observed in a population of single cells from each subject in the patient and control groups. (B) The mean number of cells bearing each nonaggregate haplotype in a population of cells from leukemia patients and healthy controls. The unpaired t test was used when the F test was not statistically significant; otherwise unpaired t test with the Welch correction was used. The 7 AML M1 patients at diagnosis and prior treatment are marked by open triangles. Horizontal lines refer to mean values.