Plasma Contains Ultra-short Single-stranded DNA in Addition to Nucleosomal cfDNA

Plasma cell-free DNA is a widely used biomarker for diagnostic screening. We introduce uscfDNA-seq, a single-stranded cell-free DNA NGS pipeline, which bypasses previous limitations to reveal a novel population of ultrashort single-stranded cell-free DNA in plasma with a modal size of 50nt. This species of cfDNA aligns predominantly to the nuclear genome and could potentially be used for novel biomarker discovery. ### Competing Interest Statement David Wong is a consultant to GSK, Mars-Wrigley, Colgate Palmolive and has equity in Liquid Diagnostics LLC.