Elevated minisatellite mutation rate in the post-chernobyl families from ukraine

Abstract

Germline mutation at eight human minisatellite loci has been studied among families from rural areas of the Kiev and Zhitomir regions of Ukraine, which were heavily contaminated by radionuclides after the Chernobyl accident. The control and exposed groups were composed of families containing children conceived before and after the Chernobyl accident, respectively. The groups were matched by ethnicity, maternal age, parental occupation, and smoking habits, and they differed only slightly by paternal age. A statistically significant 1.6-fold increase in mutation rate was found in the germline of exposed fathers, whereas the maternal germline mutation rate in the exposed families was not elevated. These data, together with the results of our previous analysis of the exposed families from Belarus, suggest that the elevated minisatellite mutation rate can be attributed to post-Chernobyl radioactive exposure. The mechanisms of mutation induction at human minisatellite loci are discussed.

Figures

Figure 1

Map showing the study area

Figure 2

Minisatellite germline mutation rates in the control and exposed groups from Ukraine, Belarus, and the United Kingdom. A, Single-locus estimates of paternal mutation rates in the control and exposed groups from Ukraine (Wilcoxon matched pairs test, Z=2.10; P=.0357) and exposed group form Belarus (Z=2.52; P=.0117). B, Comparison of paternal and maternal minisatellite germline mutation rates in the exposed and nonexposed families of different origin. Data for the Belarus and U.K. families are taken from previous studies by Dubrova et al. (1996, 1997).

Figure 3

Minisatellite paternal mutation rate, paternal age and the year of conception in the control and exposed groups from Ukraine and Belarus. A, The lack of correlation between mutation rate and the paternal age in the control and exposed fathers (Kendall's nonparametric correlation: control Ukrainian fathers, τ=-0.091, P=.6808; exposed Ukrainian fathers, τ=0.033, P=.8695; exposed Belarus fathers, τ=-0.110, P=.5820). B, Paternal mutation rate and the year of conception in the control and exposed group from Ukraine. The dashed lines represent paternal mutation rates (± 95% CI) for the whole control and exposed groups. Data for the Belarus families are taken from previous studies by Dubrova et al. (1996, 1997).

Figure 4

Spectrum of paternal germline mutations in the control and exposed groups from Ukraine and Belarus. A, Distribution of progenitor allele sizes for mutants (Kolmogorov-Smirnov test for all paired comparisons, P>.10; Kruskal-Wallis ANOVA, H=3.09; P=.2129). B, Distribution of size changes for paternal mutations (Kolmogorov-Smirnov test for all paired comparisons, P>.10; Kruskal-Wallis ANOVA, H=3.27; P=.1953). Data for the Belarus families are taken from previous studies by Dubrova et al. (1996, 1997).