title: Skewed segregation of the mtDNA nt 8993 (T-->G) mutation in human oocytes.
abstract: Rapid changes in mtDNA variants between generations have led to the bottleneck theory, which proposes a dramatic reduction in mtDNA numbers during early oogenesis. We studied oocytes from a woman with heteroplasmic expression of the mtDNA nt 8993 (T-->G) mutation. Of seven oocytes analyzed, one showed no evidence of the mutation, and the remaining six had a mutant load > 95%. This skewed expression of the mutation in oocytes is not compatible with the conventional bottleneck theory. A possible explanation is that, during amplification of mtDNA in the developing oocyte, mtDNA from one mitochondrion is preferentially amplified. Thus, subsequent mature oocytes may contain predominantly wild-type or mutant mitochondrial genomes.
authors.affiliation: Murdoch Institute, Royal Children's Hospital, Melbourne, Victoria, Australia.
authors.forename: R B
authors.initials: RB
authors.lastname: Blok
authors.forename: D A
authors.initials: DA
authors.lastname: Gook
authors.forename: D R
authors.initials: DR
authors.lastname: Thorburn
authors.forename: H H
authors.initials: HH
authors.lastname: Dahl
mesh_terms: D015925:Cryopreservation; D004272:DNA, Mitochondrial / Q000096:biosynthesis / Q000097:blood / Q000235:genetics*; D005260:Female; D005784:Gene Amplification; D018392:Genomic Imprinting; D006801:Humans; D008297:Male; D008928:Mitochondria / Q000378:metabolism; D008957:Models, Genetic; D009865:Oocytes / Q000166:cytology / Q000502:physiology*; D009866:Oogenesis; D010375:Pedigree; D017354:Point Mutation; D016133:Polymerase Chain Reaction
chemical_list: D004272:DNA, Mitochondrial