title: Heterologous mitochondrial DNA recombination in human cells.
abstract: Inter-molecular heterologous mitochondrial DNA (mtDNA) recombination is known to occur in yeast and plants. Nevertheless, its occurrence in human cells is still controversial. To address this issue we have fused two human cytoplasmic hybrid cell lines, each containing a distinct pathogenic mtDNA mutation and specific sets of genetic markers. In this hybrid model, we found direct evidence of recombination between these two mtDNA haplotypes. Recombinant mtDNA molecules in the hybrid cells were identified using three independent experimental approaches. First, recombinant molecules containing genetic markers from both parental alleles were demonstrated with restriction fragment length polymorphism of polymerase chain reaction products, by measuring the relative frequencies of each marker. Second, fragments of recombinant mtDNA were cloned and sequenced to identify the regions involved in the recombination events. Finally, recombinant molecules were demonstrated directly by Southern blot using appropriate combinations of polymorphic restriction sites and probes. This combined approach confirmed the existence of heterogeneous species of recombinant mtDNA molecules in the hybrid cells. These findings have important implications for mtDNA-related diseases, the interpretation of human evolution and population genetics and forensic analyses based on mtDNA genotyping.
authors.affiliation: Department of Neurology and Neuroscience, Weill Medical College of Cornell University, New York, NY, USA.
authors.forename: Marilena
authors.initials: M
authors.lastname: D'Aurelio
authors.forename: Carl D
authors.initials: CD
authors.lastname: Gajewski
authors.forename: Michael T
authors.initials: MT
authors.lastname: Lin
authors.forename: William M
authors.initials: WM
authors.lastname: Mauck
authors.forename: Leon Z
authors.initials: LZ
authors.lastname: Shao
authors.forename: Giorgio
authors.initials: G
authors.lastname: Lenaz
authors.forename: Carlos T
authors.initials: CT
authors.lastname: Moraes
authors.forename: Giovanni
authors.initials: G
authors.lastname: Manfredi
mesh_terms: D015139:Blotting, Southern; D003001:Cloning, Molecular; D004272:DNA, Mitochondrial; D006239:Haplotypes; D006801:Humans; D006822:Hybrid Cells; D008928:Mitochondria / Q000235:genetics*; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D011995:Recombination, Genetic
chemical_list: D004272:DNA, Mitochondrial