WU-CRISPR: characteristics of functional guide RNAs for the CRISPR/Cas9 system

Table 2 gRNA feature filters that were applied before the SVM modeling process

Filtered features	Excluded value	Enrichment ratio for non-functional gRNA
gRNA folding (∆G)	< −8 kcal/mol	15.8
Duplex binding (∆G)	< −22 kcal/mol	3.5
GC content	>80 %	30.7
UUU in the seed region	True	10.5
Repetitive bases	True	4.2
Position 19	U	2.6
Position 20	C or U	2.5

Free energy (∆G) was calculated by RNAfold for gRNA self-folding and by the nearest neighbor method for binding stability of gRNA–target duplex

ISSN: 1474-760X