Zymo-Seq Cell Free DNA WGBS Library Kit provides an optimized and reliable workflow for whole genome bisulfite sequencing (WGBS) library preparation from cell-free DNA (cfDNA). This all-inclusive kit features a straightforward procedure capable of preparing high-quality methyl-seq libraries from as little as 5 ng of cfDNA. The process is completed in three basic steps: bisulfite conversion, direct adapter ligation, and index PCR amplification. The initial bisulfite treatment is gentle on cfDNA yet effective in converting any unmodified cytosines into uracil. Next, the innovative splinted adapters capture and directly ligate the Illumina-compatible adapters onto any size DNA fragment, allowing for sequencing of nicked, damaged, and short DNA fragments that may have otherwise been discarded with traditional library prep methods. The direct ligation of the adapters also eliminates the need for second strand synthesis, end repair, and dA tailing steps, thus reducing bias by preserving the integrity of any native methylation that is present on the fragment termini. Finally, the adapter-ligated cfDNA is indexed and amplified via PCR with Zymo-Seq UDIs, generating libraries that are ready for sequencing on any Illumina instrument.