This study relied upon a targeted analysis of CpG-rich sequences known to regulate a specific gene. Using a combination of bisulfite treatment, PCR amplification of selected regions, and pyrosequencing, the authors were able to detect and quantify small changes in methylation rates for individual bases. It remains impractical to use these sorts of targeted approaches to examine the entire methylome, but, as we saw previously for a mass-spec-based validation or a reversal with 5-azaC, some sort of validation is essential for complementing genome-wide screenings.
