In a discovery that has flabbergasted geneticists, researchers have shown that plants can overwrite the genetic code they inherit from their parents, and revert to that of their grandparents.The finding, published in "Nature", challenges textbook rules of inheritance, which state that children simply receive combinations of the genes carried by their parents.</p><p><a href="http://www.nature.com/news/2005/050321/pf/050321-8_pf.html#B1">Cress overturns textbook genetics</a>