Influences of GPx-1 gene polymorphism on the frequencies (%) of moderate and high DNA damage of the total group. N = sample size. The data correspond to the means and to the standard error of mean (SEM) of the frequencies (%) of comets of class 1 and 2 (moderate damage) and of comets of class 3 and 4 (elevated damage) with respect to the total damages. P-values were generated by the Kruskall-Wallis test. The lower-case letters indicate significant differences detected by the Mann-Whitney U test in the 2-to-2 comparisons between genotypes: for moderate damage, a = significant compared to b (p = 0.002); for elevated damages, c = significant compared to d (p = 0.004).