DNA methylation plays a critical role in the regulation of gene expression and is known to be an essential mechanism for guiding normal cellular development and maintaining tissue identities. Numerous studies have implicated aberrant methylation in the etiology of many human diseases including cancer. Illumina’s Infinium Methylation Assay provides quantitative methylation measurement at the single-CpG-site level, offering the highest resolution for understanding epigenetic changes.

HumanMethylation27 BeadChip
With the HumanMethylation27 BeadChip researchers can quantitatively interrogate 27,578 CpG loci covering more than 14,000 genes at single-nucleotide resolution. This high-density panel lets researchers profile up to 12 samples in parallel.

Powerful Infinium chemistry
The Infinium Methylation Assay detects cytosine methylation at CpG islands based on highly multiplexed genotyping of bisulfite-converted genomic DNA (gDNA). Upon treatment with bisulfite, unmethylated cytosine bases are converted to uracil, while methylated cytosine bases remain unchanged. The assay interrogates these chemically differentiated loci using two site-specific probes, one designed for the methylated locus (M bead type) and another for the unmethylated locus (U bead type). Single-base extension of the probes incorporates a labeled ddNTP, which is subsequently stained with a fluorescence reagent. The level of methylation for the interrogated locus can be determined by calculating the ratio of the fluorescent signals from the methylated vs unmethylated sites.