title: Single lymphocytes from two healthy individuals with mitochondrial point heteroplasmy are mainly homoplasmic.
abstract: The nature of mitochondrial DNA heteroplasmy is still unclear. It could either be caused by two mitochondrial DNA (mtDNA) haplotypes coexisting within a single cell or by an admixture of homoplasmic cells, each of which contains only one type of mtDNA molecule. To address this question, single lymphocytes were separated by flow cytometry assisted cell sorting and analyzed by cycle sequencing or minisequencing. To attain the required PCR sensitivity, the reactions were carried out on the surface of chemically structured glass slides in a reaction volume of 1-2 microl. In this study, blood samples from two healthy donors showing mitochondrial point heteroplasmy in direct sequencing (195Y and 234R, respectively) were analyzed. Nearly 96% of single lymphocytes tested were found to be in a homoplasmic state, but heteroplasmic cells were also detected. These results suggest that mitochondrial point heteroplasmy in blood may well be mainly due to the mixture of homoplasmic cells.
authors.affiliation: Institute of Legal Medicine, Albert Ludwig University Freiburg, Albertstrasse 9, 79104 Freiburg, Germany. sabine.lutz-bonengel@uniklinik-freiburg.de
authors.forename: Sabine
authors.initials: S
authors.lastname: Lutz-Bonengel
authors.forename: Timo
authors.initials: T
authors.lastname: Sänger
authors.forename: Walther
authors.initials: W
authors.lastname: Parson
authors.forename: Helena
authors.initials: H
authors.lastname: Müller
authors.forename: Joachim W
authors.initials: JW
authors.lastname: Ellwart
authors.forename: Marie
authors.initials: M
authors.lastname: Follo
authors.forename: Bernhard
authors.initials: B
authors.lastname: Bonengel
authors.forename: Harald
authors.initials: H
authors.lastname: Niederstätter
authors.forename: Marielle
authors.initials: M
authors.lastname: Heinrich
authors.forename: Ulrike
authors.initials: U
authors.lastname: Schmidt
mesh_terms: D000328:Adult; D017931:DNA Primers; D004272:DNA, Mitochondrial / Q000235:genetics*; D005434:Flow Cytometry; D006801:Humans; D008214:Lymphocytes / Q000502:physiology*; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA
chemical_list: D017931:DNA Primers; D004272:DNA, Mitochondrial