THE COOPERATIVE GENE: How Mendel's Demon Explains the Evolution of Complex Beings

The field of genetics rarely makes for easy reading, but Ridley's anecdotal approach lightens the load, At times his writing conveys a sense of awe at the vast complexity of the universe, elevating his topic to appropriately sublime heights. His interest lies in the role that error has played in our four-trillion-year journey toward ever more complex forms, from single-celled eukaryotes to humans, and possibly beyond. Two kinds of genetic mistakes occur in reproduction, the author tells us, one accidental, the other intentional. The former results in copying errors similar to the way a simple message in a game of "telephone" can be drastically altered as it relays from player to player. The latter results from genes that harm the body by uncooperative and selfish acts. As Ridley, a biologist at Oxford University and a regular contributor to Scientific American, Nature and the New York Times, shows, both kinds of error threaten the existence of complex life, and sex provides the solution, by concentrating errors in particular offspring and leaving others virtually error-free. Perhaps not unexpectedly, though, sex poses problems of its own, because natural selection, if unchecked, would seem to favor the selfish gene, making the evolution of complex life impossible. The evolutionary balancing act is achieved through a manner of genetic inheritance first described by Gregor Mendel. The so-called Mendel's demon, a mechanism of inheritance with a random component, directs the laws of biology toward creativity rather than destruction. As the author puts it, "Somewhere between the bacteria and us—perhaps at about the stage of simple worms—God did have to start to play dice." (June)