Wednesday, May 25, 2016

Still selfish after all these years?

The 40th anniversary of the publication of Richard Dawkins’ The Selfish Gene is a cause for celebration, as I’ve said.

This anniversary has also reawakened the debate about the book’s title. Do we still think genes are “selfish”? Siddhartha Mukherjee's The Gene makes no mention of the idea, while talking about pretty much everything else. It’s no surprise that Dawkins sticks to his guns, of course. He justifies it in this fashion:

"If you ask what is this adaptation good for, why does the animal do this – have a red crest, or whatever it is - the answer is always, for the good of the genes that made it. That is the central message of The Selfish Gene and that remains true, and reinforced."

This is a statement crafted to brook no dissent. It says nothing about selfishness of genes. It says that adaptations are, well, adaptive, in that they help the organism survive and pass on its genes. But for a gene to be metaphorically selfish, it must surely promote its survival at the expense of other genes.

I’m not going to rehearse again the argument that the “selfish gene” promotes the misconception – which I suspect is now very common – that different genes, not different alleles of the same gene, compete with one another. (In the comment to my blog post above, Matt Ridley points out that there can be exceptions, but at such a stretch as to prove the rule. Still, as Matt says, we're basically on the same page.) The fact is that genes can only propagate with the help of other genes. John Maynard Smith recognized this in the 1970s, and so did Dawkins. He chose the wrong title, and the wrong metaphor, and wrote a superb book about them.

I find it curious that there’s such strong opposition to that fact. For example, I’m struck by how, when the selfish-gene trope is questioned, defenders will often point to rare circumstances in which genes really do seem to be “selfish” – which is to say, where propagation of a gene might be deleterious to the success of an organism (and thus to its other genes). It is hard to overstate how bizarre this argument is. It justifies a metaphor designed to explain the genetic basis of evolutionary adaptation by pointing to a situation in which genetic selection is non-adaptive. You might equally then say that, when genes are truly selfish, natural selection doesn’t “work”.

What is meant to be implied in such arguments is that this selfishness is always there lurking in the character of genes, but that it is usually masked and only bursts free in exceptional circumstances. That, of course, underlines the peril of such an anthropomorphic metaphor in the first place. The notion that genes have any “true” character is absurd. Genetic evolution is a hugely complex process – far more complex than Dawkins could have known in 1976. And complex processes are rarely served well by simple, reductionistic metaphors.

Think of it this way. There are situations in which Darwinian natural selection favours the emergence of sub-optimal fitness (for example, here). This is no big surprise, and certainly doesn’t throw into doubt the fundamental truth of Darwin’s idea. However, we could then, in the spirit of the above, argue that the real character of natural selection is to favour the less-than-fittest, but this is usually masked by the emergence of optimal fitness.

There is an old guard of evolutionary theorists, battle-scarred from bouts with creationism and intelligent design, who are never going to accept this, and who will never see why the selfish gene has become a hindrance to understanding. They can be recognized from the emotive hysteria of their responses to any such suggestion – you will find them clearly identified in David Dobbs’ excellent response to criticisms of his Aeon article on the subject. It is a shame that they have fallen into such a polarized attitude. As the other responses to David’s piece attest, the argument has moved on.

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