Fig. 1

Mutant and mutation frequencies in the lungs of gpt delta mice administered the extracts. The data used to estimate the total mutant and mutation frequencies and the number of animals for each group were shown in Additional file 1: Table S1. The frequencies of base substitutions (G-to-A transition, G-to-T transversion, or A-to-T transversion) were calculated by dividing the number of mutants or mutations of each base substitution in an animal by the total frequency shown in Additional file 1: Table S1. Panels a, b, and c show the mutant frequency in mice administered the 1980, 1990, and 2010 extract, respectively. Panels d, e, and f show the mutation frequency in mice administered the 1980, 1990, and 2010 extract, respectively. Blue, green, red, and yellow lines show mutant/mutation frequency of total, G-to-A transition, G-to-T transversion, and A to T transversion. Symbols and bars indicate the average values and SD. *P < 0.05; **P < 0.01