19 July 2009 by Fern Elsdon-Baker
Magazine Issue 2717
THE notion of the "selfish gene" is the most successful scientific metaphor of the past 30 years, followed not far behind by "the extended phenotype". Both were coined by Richard Dawkins and are, as it happens, the titles of his first popular science books.
The Selfish Gene's message was that evolution is about the natural selection of genes, and genes alone. Dawkins sees them as the best candidates to be evolution's units of replication. As such, the genes that are passed on are those whose consequences serve their own interests at gene level - that is, to continue being replicated - and do not necessarily serve the interests of the organism at a larger level, or at the level of groups of organisms. It is "as if" these genes are being selfish, not that they are really selfish.The Extended Phenotype develops this idea, arguing that in their drive for survival and replication, genes extend their influence beyond the appearance, or phenotype, of an individual and into the world where it also affects their chance of survival. Think of the beaver's dam or spider's web.
For reasons to do with how science is communicated, a human love of simple narratives, and Dawkins's energetic advocacy of these metaphors, the public has been left with a view of evolution and Darwinism which does not truly reflect thinking among evolutionary biologists. This view also perpetuates the existence of "opposing camps" when there is no need. Worse, it skews popular notions of Darwinism. This is why these metaphors are so important: metaphors stretch to the heart of "what science is for" and to the kind of answers it can provide.
Take heredity. If you only read Dawkins, you might think that the case has long been closed on how it works. In fact, there are competing perspectives stretching back over 150 years. Darwin himself was a pluralist and proposed a theory of heredity that allowed not only for the inheritance of latent characteristics but also for the environment to play a role in it. According to Darwin and many who followed, the environment could even have an impact on the germ cells: in other words, the gene line is not necessarily "immortal".
Research reflecting this plurality survived outside the mainstream throughout the 20th century. Today, building on the legacy of work by researchers such as Conrad Waddington or Barbara McClintock, increasing numbers of biologists find it hard to doubt the environment has a powerful impact on gene expression during an organism's lifetime.
The public's largely Dawkinsian view will be further challenged by research now emerging that may point to this kind of environmental influence being passed on to offspring epigenetically. Researchers have known for some time about transgenerational epigenetic effects in plants and fungi, and it is becoming clear that they might occur in animals too.
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Read more here/Leia mais aqui.
Fern Elsdon-Baker is head of the British Council's Darwin Now project and author of The Selfish Genius, published this month.
