title: Frequency and pattern of heteroplasmy in the control region of human mitochondrial DNA.
abstract: In this work, we present the results of the screening of human mitochondrial DNA (mtDNA) heteroplasmy in the control region of mtDNA from 210 unrelated Spanish individuals. Both hypervariable regions of mtDNA were amplified and sequenced in order to identify and quantify point and length heteroplasmy. Of the 210 individuals analyzed, 30% were fully homoplasmic and the remaining presented point and/or length heteroplasmy. The prevalent form of heteroplasmy was length heteroplasmy in the poly(C) tract of the hypervariable region II (HVRII), followed by length heteroplasmy in the poly(C) tract of hypervariable region I (HVRI) and, finally, point heteroplasmy, which was found in 3.81% of the individuals analyzed. Moreover, no significant differences were found in the proportions of the different kinds of heteroplasmy in the population when blood and buccal cell samples were compared. The pattern of heteroplasmy in HVRI and HVRII presents important differences. Moreover, the mutational profile in heteroplasmy seems to be different from the mutational pattern detected in population. The results suggest that a considerable number of mutations and, particularly, transitions that appear in heteroplasmy are probably eliminated by drift and/or by selection acting at different mtDNA levels of organization. Taking as a whole the results reported in this work, it is mandatory to perform a broad-scale screening of heteroplasmy to better establish the heteroplasmy profile which would be important for medical, evolutionary, and forensic proposes.
authors.affiliation: Biological Anthropology Unit, Department BABVE, Faculty of Sciences, Autonomous University of Barcelona, 08193, Bellaterra (Barcelona), Spain. cristina.santos@uab.cat
authors.forename: Cristina
authors.initials: C
authors.lastname: Santos
authors.forename: Blanca
authors.initials: B
authors.lastname: Sierra
authors.forename: Luis
authors.initials: L
authors.lastname: Alvarez
authors.forename: Amanda
authors.initials: A
authors.lastname: Ramos
authors.forename: Elisabet
authors.initials: E
authors.lastname: Fernández
authors.forename: Ramón
authors.initials: R
authors.lastname: Nogués
authors.forename: Maria Pilar
authors.initials: MP
authors.lastname: Aluja
mesh_terms: D001483:Base Sequence; D004272:DNA, Mitochondrial / Q000145:classification / Q000235:genetics*; D006801:Humans
chemical_list: D004272:DNA, Mitochondrial