杏吧原创

IN the 30 years since Richard Dawkins wrote The Selfish Gene, it has been lauded and criticised like no science book since Darwin鈥檚 On The Origin of Species. Those who were not around when it was published may find it hard to appreciate the impact it had on millions of non-academic readers. For some, it transformed their sense of how they fitted into the grand scheme of things: they were told that natural selection promotes the survival not of ourselves but of our genes, and that we are the expendable vehicles which they temporarily inhabit.

The book was denounced in some quarters partly out of fears that it might encourage reactionary social attitudes. But over the years those attacks have subsided, and the gene鈥檚 eye view, which Dawkins originally propounded only as one possible way of looking at things, has come to be regarded as the only way of looking at things.

Some scientists and philosophers still have misgivings. In his new book Denis Noble, who is professor of cardiovascular physiology at the University of Oxford, focuses on one of the most commonly expressed concerns: the obsession with genes and the reductionist thinking that the gene-centred paradigm sometimes fosters.

Noble鈥檚 book takes the form of a personal essay, a disquisition on the meaning of life, ranging from medicine and evolution to linguistics and philosophy. Some of his arguments are less persuasive than others. He observes, for example, that Dawkins anthropomorphises his selfish gene, depicting it as an active entity exploiting the organism, whereas it could equally well be thought of as an inert page of instructions. However, Dawkins spelled out more than once the metaphorical nature of his model, with reminders that the gene could not in concrete terms 鈥渨ant鈥� anything.

Noble is more effective in other areas, such as in his analysis of the highly complex ways that genes interact with other genes, with the tens of thousands of different proteins they generate, with the cellular environment and with the wider environment of the organism. This is Noble鈥檚 territory: he is a founder of the field of integrative systems biology, which sets out to investigate how genes are constrained by these interactions.

Perhaps his strongest argument concerns the arrow of causality. A basic premise of the gene-centred paradigm is that while information can be passed from genes to organism, nothing that happens to the organism can ever affect the genes or be transmitted to future generations. Yet as Noble points out, 鈥渋n multi-cellular organisms there is a level at which a form of such inheritance is rampant鈥�. The DNA code may be unchanged, but in some types of cell differences arise in the way the genes are expressed 鈥� and they transfer the information concerning their acquired pattern of gene expression to their daughter cells. It is called epigenetic inheritance.

鈥淎 host of genetic elements defy the rules of inheritance鈥�

Furthermore, science has moved on since Dawkins鈥檚 book treated the gene as the irreducible unit of inheritance, in the same way that atoms are no longer regarded as the irreducible units of matter. Recently, the gene has come to appear less and less like the irreducible unit of anything. There have been other developments too. A host of rogue genetic elements have come to light that defy the Mendelian rules of inheritance. Such entities are ubiquitous: they have been found in organisms throughout the plant and animal kingdoms right down to the slime moulds.

Do these developments detract from Dawkins鈥檚 contribution to science? Not really. Dawkins was never a determinist: he has always assured us that we can rebel against the dictates of our genes. His thinking is no more incompatible with the work that epigeneticists and systems biologists are doing than the work of the weaver is incompatible with that of the spinner.

Noble approves of much of what Dawkins says. Indeed a weakness of his book is that it never specifies its target. Another weakness comes when he announces that his way of seeing things requires an entirely new kind of philosophy, which he then expounds. These final chapters will leave many readers with a sensation that Dawkins鈥檚 readers never experienced, namely: 鈥淚 don鈥檛 understand what you鈥檙e trying to tell me.鈥�