Length heteroplasmy of sturgeon mitochondrial DNA: an illegitimate elongation model.
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.
Buroker
N E
NE
School of Medicine, Department of Pediatrics, University of Washington, Seattle 98195.
Brown
J R
JR
Gilbert
T A
TA
O'Hara
P J
PJ
Beckenbach
A T
AT
Thomas
W K
WK
Smith
M J
MJ
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
D004272:DNA, Mitochondrial