Fig. 4

Distribution of pre-processed reads. The figure displays jittered boxplots (a, b), stacked density plots (c, d), and stacked histograms (e, f) of the forward reads. All plots give a summary of number of reads split by experimental variables; sex (male and female: a, c, e) and time (early and late: b, d, f). The legend on top of the figure shows the QC variables where Original_R1 indicates the forward reads before preprocessing, TrimQ25_R1 shows the forward after trimming at 25 Phred score, and NophiX_R2 shows the reverse reads after removing phiX contamination. Adding jitter on top of the boxplots made the variables more insightful. The line that divides the box plots into two parts and the dotted line on density plots and histograms represents the median of the data