title: Length heteroplasmy of sturgeon mitochondrial DNA: an illegitimate elongation model.
abstract: Extensive length polymorphism and heteroplasmy (multiple forms within an individual) of the D-loop region are observed in mitochondrial DNA of the white sturgeon (Acipenser transmontanus). The nucleotide sequence of this region, for both a short and a long form, shows that the differences are due to variable numbers of a perfect 82-bp direct repeat. We propose a model for the replicative origin of length differences, involving a competitive equilibrium between the heavy strand and the D-loop strand. This model suggests that frequent misalignment in the repeat region prior to elongation, facilitated by a stable secondary structure in the displaced strand, can explain both the polymorphism and heteroplasmy in this species.
authors.affiliation: School of Medicine, Department of Pediatrics, University of Washington, Seattle 98195.
authors.forename: N E
authors.initials: NE
authors.lastname: Buroker
authors.forename: J R
authors.initials: JR
authors.lastname: Brown
authors.forename: T A
authors.initials: TA
authors.lastname: Gilbert
authors.forename: P J
authors.initials: PJ
authors.lastname: O'Hara
authors.forename: A T
authors.initials: AT
authors.lastname: Beckenbach
authors.forename: W K
authors.initials: WK
authors.lastname: Thomas
authors.forename: M J
authors.initials: MJ
authors.lastname: Smith
mesh_terms: D000818:Animals; D001483:Base Sequence; D004261:DNA Replication; D004272:DNA, Mitochondrial / Q000235:genetics* / Q000378:metabolism; D005399:Fishes / Q000235:genetics*; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D012150:Polymorphism, Restriction Fragment Length; D012091:Repetitive Sequences, Nucleic Acid
chemical_list: D004272:DNA, Mitochondrial