Transversion

During DNA replication in the germ line of mice, the oxidized base 8-oxoguanine (8-oxoG) causes spontaneous and heritable G to T transversion mutations.

[3] These mutations occur in different stages of the germ cell lineage and are distributed throughout the chromosomes.

If the mutation occurs at a site that is not involved with the shape of a protein or the structure of an enzyme or its active site, the mutation will not have a significant effect on the cell or the enzymatic activity of its proteins.

[4] Of the natural nitrogenous bases of DNA, guanine is most prone to oxidation.

In smokers’ lung cancer, the prevalence of G-T transversions is 30% compared to that of 12% in non-smokers.

Illustration of a transversion: each of the 8 nucleotide changes between a purine and a pyrimidine (in red). The 4 other changes are transitions (in blue).