DNA is the molecule by which hereditary information is transmitted from generation to generation. Today the role of DNA is well known, but at one time hardly any biologist would have bet on it. Any poll of biologists before about 1950 would have shown overwhelming support for the idea of proteins as life’s information molecule. Compared with the seemingly monotonous, featureless structure of DNA, the three-dimensional structures of proteins are highly diverse. Proteins carry out most of the essential activities in the life of a cell, and so it seemed logical to assume that they would play a key role in heredity, too. But while proteins do play a role in heredity, they play a supporting role in looking after the DNA—rather like the way worker bees are essential in maintaining the queen bee, who alone is able to reproduce.