Figure 4

% GC distribution of sequenced reads. (A) Expected (blue line) and actual (red line) % GC content present in total sequenced reads. Representative reads from a single sample are shown. (B) Elucidation of source of high and low % GC peaks in the sequencing reads. Model depicts captured fcDNA fragments (blue lines with sequenced 50 base reads shown on ends) containing methylated CpG sites which allow for capture (red circles). Arrows indicate the contribution of each read to the low % GC peak (methylated CpG sites are located in the middle of the fragment and thus fall outside 50 base read) and the high % GC peak (methylated CpG sites are located near the edge of the fragment and thus contained within 50 base read). (C) Expected (blue line) and actual (red line) % GC content present in non-overlapping sequenced reads. Representative reads from a single sample are shown.