Navigating your way through the sea ofinformation that is contained in the DNAof a genome can be a daunting task. Thehuman genome, for example, contains about 3billion base pairs and encodes around 20,000genes. It is fortunate, therefore, that this sea ispunctuated by ‘islands’ that mark the locations ofimportant features. CpG islands, for example,mark the start of genes so reliably that they wereused to identify genes in the pre-genomics era,before sequence information was so readily available.Despite this, we still do not fully understandwhy such islands are associated with essential DNAfeatures, or which properties of these islands arecrucial to their function.
- CpG islands
- DNA methylation