Why do some identical twins look so different from each other? Could your eating habits during puberty have an impact on the genetic makeup of your grandkids? These are just two of the startling questions raised by the science of epigenetics, as this "deleted" chapter from David Epstein's book The Sports Gene explains.
Before Charles Darwin, the leading evolutionary theorist was Jean-Baptise Lamarck, who believed organisms acquired traits over their lifetimes that they then passed onto their children. This theory has been roundly disproved...but in the case of roundworms, Lamarck was actually right.