The Gene: An Intimate History

by Siddhartha Mukherjee

The gene, Schrödinger posited, had to be made of a peculiar kind of chemical; it had to be a molecule of contradictions. It had to possess chemical regularity—otherwise, routine processes such a copying and transmission would not work—but it also had to be capable of extraordinary irregularity—or else, the enormous diversity of inheritance could not be explained. The molecule had to be able to carry vast amounts of information, yet be compact enough to be packaged into cells. Schrödinger imagined a chemical with multiple chemical bonds stretching out along the length of the “chromosome fiber.” Perhaps the sequence of bonds encoded the code script—a “variety of contents compressed into [some] miniature code.” Perhaps the order of beads on the string carried the secret code of life. Similarity and difference; order and diversity; message and matter. Schrödinger was trying to conjure up a chemical that would capture the divergent, contradictory qualities of heredity—a molecule to satisfy Aristotle. In his mind’s eye, it was almost as if he had seen DNA.