Fig. 4

Characterization of the DNA break point. a Fold changes in error rates across all substitution classes were compared between PBL and plasma DNA samples. The fold change was calculated by dividing the substitution rate at each position by the average rate of 1 − 50 bp. The distribution of fold changes in 1 − 50 bp was box-plotted. Above the box plots, the observed fold change at the first and the second bases was marked for comparison. For better discrimination between the groups, plasma data are displayed on a grey background. b The distribution of quality scores of total bases, including low quality bases, is plotted according to the position of reads. c Mononucleotide frequencies around the DNA break point. Note: except in (b), all analyses of background alleles were performed after filtering of bases with a quality score <30