Em seq conversion module

EM-seq library preparation was performed using VAHTS Universal DNA library Prep Kit for Illumina V3 (Vazyme) and EM-seq Conversion Module (New England BioLabs) according to the manufacturer’s instruction with minor modifications. In brief, mechanically fragmented methylation control DNA (CpG methylated pUC19 and unmethylated λ DNA) alone or combined with cell-free DNA fragments was treated with VAHTS Universal DNA library Prep Kit (New England BioLabs) for end-repair, A-tailing, and ligation of EM-seq adaptor (New England BioLabs). The ligated samples were methyl-converted with EM-seq Conversion Module (New England BioLabs) per the manufacturer’s protocol. Methyl-converted DNA was purified and amplified using NEBNext Unique Dual Index Primers (New England BioLabs) and KAPA HiFi HotStart Uracil + ReadyMix (KAPA biosystems).