Epigenetic information in the genome is a layer of information ‘above’ the genome, which is used for the development of the different organs in babies and proper functioning of these organs in adults. The genetic information is the same in all organs but how this genetic information is used to make a body is partly explained by epigenetics. Epigenetic marks are chemical groups or certain proteins that are attached to DNA and programme it to function in particular ways, often for years. The epigenetic marks can also depend on environmental or nutritional factors particularly those encountered early in life.
While epigenetic marks can be very stable in adult tissues, in germ cells and early embryos there is a process of ‘epigenetic reprogramming’ by which many of the marks are removed from DNA to ‘wipe the slate clean’. This reprogramming is also important for the function of embryonic stem cells, and in reprogramming iPS cells from adult tissue cells. We study the mechanisms and functions of this remarkable process by which epigenetic memory is erased so that embryonic cells become ‘naïve’ again and can form a new body. When this erasure goes wrong there may be adverse consequences for healthy development and ageing, which can potentially extend over more than one generation. Epigenetic information may be degraded during ageing leading to functional decline of organ systems. Our insights into the mechanisms of epigenetic reprogramming may help with developing better strategies for stem cell therapies and to combat age related decline.