Scientists have long puzzled over the different fates of identical twins: both have the same genes, yet only one may develop a serious disease like cancer or autism. What's going on? Does something else besides genes determine who we are? NOVA explores this startling possibility in this program.
The "something else" turns out to be a network of chemical switches that sit on our DNA, turning genes off and on. Called collectively the epigenome, the switches appear to play a major role in everything from how our cells keep their identity to whether we contract dread diseases. Epigenetic switches may even help mold our personalities—or so it appears to Canadian researchers studying a group of epigenetically modified rats.
Website: http://www.pbs.org/wgbh/nova/genes/
