Ultra-mild bisulphite sequencing for DNA methylation analysis from low-input clinical specimens.

Area of Science:

• Epigenetics and Genomics
• Molecular Biology
• Clinical Diagnostics

Background:

• Classical bisulphite sequencing is limited by DNA damage, especially with low-input or fragmented clinical samples.
• Existing methods struggle to provide reliable methylome data from precious, scarce clinical DNA specimens.

Purpose of the Study:

• To evaluate the practical re-engineering of ultra-mild bisulphite sequencing (UMBS-seq) for clinical DNA analysis.
• To assess UMBS-seq's performance compared to conventional bisulphite workflows and enzymatic alternatives.

Main Methods:

• Ultra-mild bisulphite sequencing (UMBS-seq) protocol optimization.
• Benchmarking UMBS-seq against conventional bisulphite sequencing and enzymatic methods using low-input, fragmented DNA.
• Analysis of DNA damage, library complexity, GC content recovery, and C-to-U conversion efficiency.

Main Results:

• UMBS-seq significantly reduces DNA damage and chemical alterations.
• Achieved higher library yield and complexity, even with picogram levels of DNA.
• Demonstrated improved CpG/GC coverage uniformity and consistent C-to-U conversion with minimal background noise.

Conclusions:

• UMBS-seq provides technically reliable methylomes from challenging clinical samples.
• This method enables robust methylation risk scoring, turning DNA scarcity into a design advantage.
• UMBS-seq is a valuable tool for pregnancy cohorts and other studies using limited clinical material.