BOOK REVIEW : Keeping Pace With Ongoing Evolution of Genes

The Wisdom of the Genes: New Pathways in Evolution by Christopher Wills (Basic Books: $19.95; 351 pp.)

One of the greatest intellectual achievements in the history of science was Charles Darwin’s idea of evolution by natural selection. It is the cornerstone of biology, and it revolutionized humanity’s view of itself and its place in the universe.

Yet there is probably no idea in science that engenders more resistance. From Darwin’s time a century ago to the Scopes trial in 1925 to our own day, many people (including some who should know better) have refused to believe that life started once three and a half billion years ago and that every species that now exists or ever existed evolved from that event.

One of the central arguments used by the doubters is time. There isn’t enough of it, they claim, for random chance to have produced the great complexity and diversity of living creatures. Darwin himself wondered about this. How, he asked, could the complexity of the eye have come about by random shuffling? And that’s just one of the many complicated organs that evolved and work together in people and other species.

The standard answer to this question is that three and a half billion years is not just a long time but a very, very, very long time. Incomprehensibly long. Given enough time, the improbable becomes probable.

Christopher Wills, a biologist at the University of California, San Diego, has a different answer. In “The Wisdom of the Genes,” he argues that the pace of evolution has not been constant. Rather, he says, it has accelerated in time. Evolution has fostered the ability to evolve, and natural selection has favored that trait.

“Evolution is getting easier,” Wills says. “The way genes are organized, and the way mutation-causing agents act on them, facilitates the channeling of evolution in certain directions. . . . The shape and arrangement of our genes reflect three billion years of constant practice at evolving.”

In support of this view, Wills provides much evidence and many examples at the level of organisms and at the level of genes. Some of this may be tough going for the nonexperts in the crowd, but it is possible to skim those parts without losing the thread of the argument. “The Wisdom of the Genes” is meant to satisfy both general readers and professional biologists, and it largely succeeds, which is no mean feat.

Wills is not the first theorist to speculate about the pace of evolution. In recent years, Stephen Jay Gould and Niles Eldridge have argued for what they call “punctuated equilibrium”--long periods of no change followed by shorter periods of rapid change among species. Richard Dawkins has rejected that view, arguing instead that the genes themselves have a propensity for certain organization that makes evolution possible within the time available. Wills presents yet a third idea.

All this writing shows that while the central idea of evolution is indisputable among scientists, the details have yet to be worked out. “A hundred years after Darwin, our ideas about evolution are still changing rapidly,” Wills says.

Opponents may take this as a sign of the weakness of the idea. In fact, it is one of the strengths. Despite a lifetime of work gathering data and analyzing it, Darwin did not have all the answers. Far from it. He didn’t have a clue, for example, about the mechanism of heredity, which we now know to be the genes and the DNA they contain.

Darwin’s work was robust. Everything biologists have learned and every shred of evidence they have gathered since “The Origin of Species” was published in 1859 has supported the basic idea of that book. The disagreements among biologists about the mechanism of evolution should not be taken as a sign of weakness.

Similarly, there are many questions still to be answered. But the holes can be filled in without jettisoning the basic idea. As Wills notes, evolution does not speak to the question of how life began in the first place--only how it evolved once it got going. Nor is the origin of human intelligence well understood. Much work is under way on both these problems. The absence of answers shows only how hard the questions are.

Wills’ book is grounded firmly in the mainstream of biology, and it brings us up to date on its frontiers. The work begun by Darwin is far from finished.