Epigenética how it works

changes that do not affect the DNA sequence are called epigenetic – they change the way DNA is wrapped up in the nucleus. DNA wraps around proteins called histones, like cotton around a spool, to make a package called chromatin. The characteristic features that change chromatin packaging are mostly chemical changes, either to the DNA itself, by the methylation of individual DNA bases; or to the histone packaging proteins they are wound around, by modifications such as acetylation, or methylation. These modifications can make regions of chromatin more tightly packaged, in which case the genes on the DNA in that region are silenced, or more open, which switches genes on. Tsai’s team showed that environmental enrichment increases acetylation of the histone spools, which makes the chromatin package more open, activating a large number of genes.