There's more to life than the four letters of DNA, and our cells use a chemical tag known as DNA methylation to mark out certain parts of the genome, helping cells to remember what they're doing. And, as you might expect, it's pretty important. Plus, how your GCSE success could be encoded in your genes, an important molecular cause of autism identified, and an illuminating gene of the month. Like this podcast? Please help us by supporting the Naked Scientists