Hi, I am a beginner to chip-seq analysis using Galaxy. I have received my data and did fastqc quality check. I was wondering if I could get some help in trying to understand what is needed to be done in order to correctly prep the raw data for mapping and peak calling. Also, is it necessary to trim adapters before doing mapping as some of my datasets have one or two over-represented sequences which match the Truseq adapter sequences. I tried trim galore! and trimmomatic but when i run fastqc on the trimmed dataset, the length distribution changes from 101 all sequences to a range of 0-101.