CpG-Methylom profile

The CpG methylome profile is the comprehensive genome map that shows which CpG sites are methylated in a particular biological sample and to what extent this has occurred. CpG methylome profile is a central tool in epigenome research and describes the pattern of DNA methylation at all CpG sites (i.e. cytosine-guanine dinucleotides) in the genome of a cell or tissue.

DNA methylation is a chemical modification in which a methyl group (-CH₃) is attached to the cytosine of a CpG site. CpG sites refer to areas in the DNA where a cytosine is directly in front of a guanine (5'-C-phosphate-G-3'). These sites are hotspots for methylation.

What does the CpG methylome profile show?

• It shows a genome-wide map of the methylation levels of each CpG position (e.g. 0 % to 100 % methylated). The profile can be displayed as a heatmap, sequence file or percentage values per gene region.
• Gene regulation: High methylation in promoter regions can "switch off" genes.
• Development and cell differentiation: Different cell types have characteristic methylome patterns.
• Disease research: Changes are typical for cancer, ageing processes or epigenetic diseases.

How is a CpG methylome profile determined?

• Whole-Genome Bisulfite Sequencing (WGBS): Gold standard for complete methylome profiles.
• Reduced Representation Bisulfite Sequencing (RRBS): Cost-reduced, focused variant.
• Array-based methods (e.g. Illumina Infinium MethylationEPIC).