Saturday, 31 May 2014

The gene revolution

20th century biology saw what we might call the gene revolution - a new emphasis on and understanding of the importance of genes. A number of landmarks in the revolution might be identified: the rediscovery of Mendel's work around the turn of the century, the development of population genetics, the discovery of the structure of DNA, and the work of George Willams, William Hamilton, Richard Dawkins and others in developing a gene-oriented perspective on evolution.

What did we gain during the gene revolution? What did we lose?

We gained a renewed understanding of how useful it is to split organisms into heritable information and everything else. The genome is inherited and goes on to strongly affect evolution. The phenome is not inherited - and only affects evolution via its effect on genotypes and their distribution. The transitory nature of phenotypes means that they can be ignored in population genetic studies.

We also learned how useful it is to split the genome up into pieces and analyze the pieces - and the relationships between them, such as linkage. This perspective led to the ideas of kin selection and intragenomic conflict. Organisms had previously been regarded as harmonious wholes. The atomization of the genome during the gene revolution showed that organisms were more like loose coalition of parties with interests that are not always shared.

Famously, the gene revolution also led to the genes eye view, a means of analyzing and visualizing the operation of particular genes.

The gene revolution also seemed to result in an unhealthy focus on genes in some areas. People equated inheritance with DNA, and this led to much muddle and confusion. Part of the problem was that molecular geneticists started calling pieces of DNA 'genes' - and this usage became wildly popular, leading to people equating genes and small DNA sections. Other forms of heredity, such as cultural inheritance, became neglected during this time. This aspect of the gene revolution was quite negative. My proposal for combating this problem is to try and ensure that everyone understands that genes are not sections of nucleic acid.

The gene revolution seems to have been pretty positive overall. However, it has its critics. Many of them object to the atomization of genomes into genes. They say that gene expression is context sensitive, that genes interact during development, that traits aren't the product of single genes, that each gene influences multiple traits.

However, splitting phenomena into pieces and analyzing the pieces and their relationships is a strategy called "reductionism". Reductionism is a widely recognized as a legitimate strategy in science. It acts as bedrock for most 20th century science.

Another complaint is that a focus on the gene diverts attention from phenotypes - portraying them "passive" or ignoring them entirely.

For example, in Darwinian Fundamentalism S. J Gould wrote:

Only one causal force produces evolutionary change in Darwin’s world: the unconscious struggle among individual organisms to promote their own personal reproductive success - nothing else, and nothing higher (no force, for example, works explicitly for the good of species or the harmony of ecosystems). Richard Dawkins would narrow the focus of explanation even one step further - to genes struggling for reproductive success within passive bodies (organisms) under the control of genes - a hyper-Darwinian idea that I regard as a logically flawed and basically foolish caricature of Darwin’s genuinely radical intent.
The gene's eye view has been the target of the most criticism - with people saying it anthropomorphizes genes, introduces teleology into biology - and a wide range of other criticisms. Most of the criticisms of the gene's eye view appear to be ridiculous misunderstandings of it.

The gene revolution seems to have not yet hit cultural evolution. The cultural version of the gene revolution is the meme revolution, which - by most accounts - has yet to happen. This seems likely to be because of cultural evolution's scientific lag.

Cultural evolution does have the cultural equivalent of population genetics, though. Frequency analysis of memes is common. However, there is still very little work on cultural kin selection. This puts cultural evolutionary theory at a point corresponding to where organic evolutionary theory was somewhere between 1930 and 1960.

Many of the criticism of memetics are isomorphic to the criticisms of the gene oriented perspective on evolution. Sometimes the same criticisms are raised by the same people. Just as genetics proponents faced criticism for dividing the genome up into genes, so memeticists face the same criticism for dividing cultures into memes.

Some doubt that a meme revolution will ever happen:

This revolution won't happen. Because there is nothing comparable to the gene in "cultural evolution", no identifiable replicator that could serve as a foundation for a scientific theory. Dawkins, Blackmore et al. proposed the ominous "meme", but this concept never lived up to the expectations of its supporters. "Memetics" is in a permanent comatose state, with no signs of recovery.
I think this is unduly pessimistic. The split between genotype and phenotype can easily and usefully be applied to culture too: simply by saying that memes are heritable, while other aspects of culture are not. Dividing cultures up into pieces in order to analyze them makes obvious sense too - and the meme's eye view is about as useful as the gene's eye view - and its validity has been recognized by leading scientists in the field.

Memetics was ahead of its time, is all. Memes have already conquered the internet. The next generation is growing up with memes. We seem bound to see a science of them in due course. I'm still hoping that we won't have to wait for the tenures of the existing cultural anthropologists to 'expire' before we see it.

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