Disabling adapter removal process while running

[EgeDede562]

Dear Felix,

I am trying to do a quality trimming with trimgalore with fastq files that have already had their adaptor sequences removed and unfortunately I do not have access to the original files. When I run trimgalore however it autodetects the illumina adaptor and tries to remove it. Is there any way of disabling this step? or should I just increase my specificity parameter to 13-14? (as it was 1, I clipped a lot of reads by accident).

Thank you

[FelixKrueger]

You could just select an adapter sequence that doesn't exist, e.g. -a X. That way, no adapter sequence should be clipped. Cheers, Felix