Methylation Sequencing

Reveals the methylation status of genomic regions of interest with single nucleotide resolution.

DNA methylation is an important epigenetic modification influencing several critical developmental processes. Aberrations in this process, such as hypo or hypermethylation of cytosine-guanine (CpG) dinucleotides, could lead to genomic instability or transcriptional silencing, leading to the development of various diseases, including cancer, diabetes, cardiovascular and inflammatory diseases or mental disorders. Determining the exact DNA methylation status is therefore critical. Methylation sequencing (Methyl-seq or bisulfite sequencing) is a powerful tool for understanding genome-wide methylation with single nucleotide resolution and is considered a gold standard.

Why Methyl-seq?

• Provides methylation status at single base-pair resolution across the entire genome  or genomic regions of interest using next-generation sequencing (NGS) technology
• Reveals hidden epigenetic modifications enabling the detection of complex or rare methylation events

How does bisulfite sequencing work?

Treatment with bisulfite results in two different consequences based on the methylation status of cytosine—unmethylated cytosine residues will be converted to uracil while methylated cytosine (5' methylcytosine) residues will remain unmodified by the treatment. Comparison of bisulfite-treated with untreated DNA enables the identification of methylated loci.

Several strategies have been developed to understand the methylation status of a genome, including:

• Whole genome bisulfite sequencing (WGBS)
• Targeted bisulfite sequencing
• Reduced representation bisulfite sequencing (RRBS), which enriches for CpG islands
• Methylated-DNA immunoprecipitation sequencing (MeDIP-seq), which utilizes antibodies against 5-methylcytosine to enrich for methylated DNA

Roche Sequencing Solutions offers a suite of target enrichment and library preparation options for methyl-seq. Bisulfite treatment results in a significant decrease in DNA input and quality; therefore, the construction of high-quality libraries and efficient downstream amplification is critical.