PAM Filter Bug

[smleighow]

Hey all,

Looks like there's a minor bug when it goes to filter out alignments without PAMs in guideAlignments. The PAM regular expression in the code is currently "[ACGTN]GG|GG[ACGTN]", which allows "GGN" PAMs to pass through the filter. "[ACGTN]GG" should be sufficient, since getSeq fetches the PAM 5'->3' relative to the query, regardless of the aligned strand. As it stands, the current code incorrectly allows ~1-2% of alignments through the filter when using the Aguirre GeCKO data.

Best,
Scott