Statistical analysis
The whole collection of NGS data-set were showing in Table1.a.While the control1 and selective1 were referring to data generated from SE1 control group and SE1 experiment group; the control2 and selective2 were referring to data generated from SE2 control group and SE2 experiment group.The reads were the raw sequencing data and the counts were the filtered data.
For a specific crRNA sequence, its abundance (crRNA frequency) in a certain group could be calculated by its divided by the summation of all crRNA counts.(Table1.b)Further, the fold-change of a specific crRNA sequence across a screening experiment (SE1 or SE2), representing the activity of a crRNA, could be calculated the ratio between the frequency in the post selection sample (selective) and the no-selection sample (control). (Table1.b)