Strand asymmetry in human mitochondrial DNA mutations.
Replication of mitochondrial DNA is highly asymmetric between the heavy (H) and the light (L) strands. The parental H strand is displaced by the daughter H strand and remains in a single-stranded state until the daughter L strand is synthesized. To examine the effect of this asymmetric replication on mutagenesis, we determined sequences of mtDNAs from 43 human individuals. Occurrence of nucleotide substitutions at 4-fold degenerate sites was distinctly asymmetric between the two strands: G-->A and T-->C transitions were 9- and 1.8-fold more frequent on the L strand than on the H strand, respectively. This nucleotide substitution bias is consistent with the T and G abundance of the H strand as well as the A and C abundance of the L strand.
Tanaka
M
M
Department of Biomedical Chemistry, Faculty of Medicine, University of Nagoya, Japan.
Ozawa
T
T
D001482:Base Composition; D001483:Base Sequence; D003062:Codon; D004261:DNA Replication; D004272:DNA, Mitochondrial / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D017382:Reactive Oxygen Species
D003062:Codon; D004272:DNA, Mitochondrial; D017382:Reactive Oxygen Species