Fig. 1

Plots of: a the frequency of C to T base substitutions from the 5′ end of each read; b the frequency of G to A base substitutions from the 3′ end of each read; c the frequency of C to T base substitutions at read position 1 from the 5′ end of reads vs. sample age; and d the frequency of G to A base substitutions at read position 1 from the 3′ end of reads vs. sample age. The expected signal for DNA damage due to age of specimens is an increased frequency of C to T and G to A transitions at the 5′ and 3′ end of reads, respectively, as well as a correlation between the frequency of such transitions at the 1st read position and sample age