Fig. 3

Mutation hotspots (nucleotides 64, 110, 115, and 406; red squares) on gpt gene in the lungs of mice treated with the 1980, 1990, and 2010 extracts. Blue letters show the gpt sequence from nucleotide 61 to 120 and from nucleotide 361 to 420. Dotted lines represent positions of hotspots. Black letters indicate the substituted bases, and each letter indicates independent mutations observed at the hotspots. d, deletion of base(s)