CHOMP – CRISPR Search Tool
CHOMP will search for all 'n' window sized guide RNAs (gRNAs) sequences containing an NGG at the tail end. Default window size is 23.
It will report how many occurrences of this sequence are present in the target sequence (off-target sites), along with number of matching bases for each subject/query hit. You can use that to determine which gRNAs you may want to use as CRISPR target(s).
perl chomp.pl -seq usr/test.fasta -out gRNAs
-seq Sequence file to search gRNAs [required] -genome Genome sequence file(s) to BLAST search (search instead of -seq) -down Down sequence to append -up Up sequence to append -window Window size for gRNA oligo (default = 23) -ss Secondary structure prediction -out Out file name [required] -outdir Out directory name -help Shows this message
Writes 2 files under the default directory gRNAs:
Fasta file of each gRNA sequence found.
>gRNA_0:0 ATGTAGCTAGCTAGCTAGTAGGG >gRNA_1:23 AAAAAATTTTCTCTATCTAACGG >gRNA_2:24 AAAAATTTTCTCTATCTAACGGG >gRNA_3:115 TGTGATCACGTACTATTATGCGG >gRNA_4:149 AAAAATCCCATCGATCTAGCAGG >gRNA_5:154 TCCCATCGATCTAGCAGGCCCGG . . . >gRNA_16:99 ATAGTACGTGATCACAGTCATGG
Suffix digit after ':' denotes nucleotide position in sequence where gRNA was found. Ex.) gRNA_16:99
, gRNA was found starting at nucleotide position 99 in
Report with each gRNA sequence's details.
CHOMP will report how many occurrences of this sequence are present in the target sequence (off-target sites), along with the number of base pair matches (identities) for each. You can use this to determine which gRNA sequence is best to use for target.
Table is sorted in increasing order using the top identity for each gRNA sequence, and then sorted by number of occurrences, in current subject.
Developer | Bioinformatician – Decoding the world, one line at a time.
Highly motivated developer predominantly working in Linux and developing software tools. All about open source software and fascinated by working with multitudes of technologies and languages. Striving to make a positive impact in this world.