A comparison of somatic mutational spectra in healthy study populations

A comparison of mutation spectra at the hypoxanthine--guanine phosphoribosyl transferase (HPRT) gene of peri-pheral blood T-lymphocytes may provide an insight into the aetiology of somatic mutation contributing to carcino-genesis and other diseases. To increase the knowledge of mutation spectra in healthy people, we have analysed HPRT mutant T-cells of 50 healthy Russians originally recruited as controls in a study involving Chernobyl clean-up workers [I.M.Jones, H.Galick, P.Kato et al. (2002) Radiat. Res., 158, 424--442]. Reverse transcriptase--polymerase chain reactions and DNA sequencing identified 161 independent mutations among 176 thioguanine-resistant mutants. Forty mutations affected splicing mech-anisms and 27 deletions or insertions of 1--60 nt were identified. Ninety-four single base substitutions were iden-tified, including 62 different mutations at 55 different nu-cleotide positions, of which 19 had not been reported previously in human T-cells. Comparison of this base substitution spectrum with mutation spectra in a US