Library end-repair reaction introduces methylation biases in paired-end (PE) Bisulfite-Seq applications

Library construction of standard directional BS-Seq samples often consist of several steps including sonication, end-repair, A-tailing and adapter ligation. Since the end-repair step typically uses unmethylated cytosines for the fill-in reaction the filled-in bases will generally appear unmethylated after bisulfite conversion irrespective of their true genomic methylation state.

February 12, 2016 Illumina, BS-Seq, Methylation, Bismark, Data Processing