The Selfish Gene

Picture all the cars driving down a busy road. Each car wears out over time. It gets old and rusty and ends up in a scrapyard. But the detailed blueprint that designed the car stays behind as a computer file or a drawing, and it keeps stamping out new cars that drive the roads for decades.

You can think about living things in a similar way. One animal or one person is born, grows up, and eventually dies. But the DNA inside can be passed on to the next generation through offspring. Evolutionary biologist Richard Dawkins called our bodies sophisticated survival machines built to protect and carry genes.

For a long time, many people believed living things evolve to preserve their whole species. Dawkins argued that the real star of evolution's long story is not the visible individual. It is the replicator (the gene), which is copied almost perfectly inside bodies and survives down the generations. Whether evolution is best seen from the gene's point of view, or from several levels at once, like individuals and groups, is still debated among scientists today.

In nature documentaries, you often see animals do something amazing: they put themselves in danger to help others. Take ground squirrels. When a predator like a weasel or a coyote gets close, a squirrel may let out a loud alarm call. The squirrel that calls gets noticed and is more likely to be eaten. But its family nearby hears the call and can dash into their underground burrows.

On the surface, this looks like pure self-sacrifice, a flat-out loss. But do the math from the gene's point of view and you get a very different answer. Even if one squirrel dies, its siblings and children each have about a 50% chance of carrying the same genes. If several of them survive, more copies of the gene behind that warning behavior end up in the next generation.

From this angle, even the most beautiful acts of sacrifice and teamwork in nature can be explained as strategies that protect a gene's copies. Genes that drive sacrifice and cooperation ended up spreading more, which is how instincts for sacrifice and cooperation settled into animals' brains and bodies.

Because of the word "selfish," many people assume genes have an evil mind or a greedy streak, like a person. But genes have no thoughts, will, or feelings. They are just clumps of molecules made of chemicals.

Suppose a random mutation gives a gene a body trait that helps it get copied even slightly better. That gene spreads more widely, and less helpful genes fade away on their own. Natural selection (the process where individuals that fit their environment survive) works like a giant sieve. What comes out the other side looks as if genes were acting with selfish intent.

So are humans just helpless robots that do whatever their genes say? Not at all. Dawkins wrote that people, with high intelligence and culture, can make choices that go against the gene's urge to reproduce, such as using contraception. He described us as the only creatures able to rebel against the tyranny of the genes.