Strand asymmetry in human mitochondrial DNA mutations

Genomics. 1994 Jul 15;22(2):327-35. doi: 10.1006/geno.1994.1391.


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.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Composition
  • Base Sequence
  • Codon
  • DNA Replication
  • DNA, Mitochondrial / genetics*
  • Humans
  • Molecular Sequence Data
  • Oxidation-Reduction
  • Point Mutation*
  • Polymerase Chain Reaction
  • Reactive Oxygen Species


  • Codon
  • DNA, Mitochondrial
  • Reactive Oxygen Species