Understanding Evolution: The Dawkins dogma

Today we understand more about genes than in Darwin' time. Richard Dawkins states that genes change in order for themselves to survive and not for the organism to survive. This is the concept of "selfish gene"

The evolutionary biologists of today say that genes are tranferred not only by DNA but also epigenetically, that is by mechanisms other than the DNA. There is also the lateral gene transfer, where the organism gets genetic material from other organisms without being their offspring. We have now found evidence that this happens not only in bacteria and viruses, but in animals too.

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.

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.

Another area of research that could challenge Dawkins's metaphors is lateral gene transfer (LGT), which describes how an organism incorporates genetic material from another organism without being its offspring, as opposed to vertical transfer, in which genetic material is transmitted from parent to offspring.

Most of us know about LGT through antibiotic resistance, where one bacterium transfers genetic information to another that gives it immunity to a type of antibiotics. At first it seemed as if LGT affected only single-celled microbes, which reproduce asexually, but there is increasing evidence that it also occurs in animals and plants.

Source: www.newscientist.com...




[edit on 19-7-2009 by sunny_2008ny]

Christian enjoys the big words people use to identify processes they don't understand. Defintion should read:
"which means, anything other than the small aspect of things of which we know what the goshdarnshucks heck we're talking about"

The proof you're looking for is the scientifc justification of who's invited to the table.
Speak my stupid language, please!!

Very good article. Genetics and inheritance are very complex subjects and there is still a lot to discover about it.

Epigenetics are a very good example of how unexpected traits can be inherited. But we have a lot more to learn about epigenetics, what traits can be transfered by it and what traits can not be transferred.

For you S&F!

reply to post by DrDragonfly


seemed like the article was a third party observation of processes with educated guesses at best.
a summarization of goings on, if you will.
Add a couple nice words and a slight bias and you've got yourself some proof.......

Epigenetics and lateral gene transfer are the 2 emerging fields of study in genetics. We have genetic engineering but I think these two fields will tell us what exactly happens when a genetic transfer takes place, and we live as humans, but I think in nature we do not have control over our genes. So we can only go as far as our genes allow

I think it's important to be very clear about

1. what this article is saying
   
   
2. what it implies for evolutionary theory

Here's the key section.

The selfish gene metaphor claims that only genes or replicators are inherited and are essentially immortal, and it offers an interpretation of evolutionary biology in that light.

We are testing that empirical claim and finding that things are a lot more complicated and subtle. This must mean that as an organising interpretation of evolutionary biology, the metaphor of the selfish gene and, by extension, that of the extended phenotype, are insufficient.

The article is not saying that the selfish gene metaphor is wrong. It does claim, however, that the metaphor is inadequate because the mechanics of gene transfer go beyond simple heredity - getting our genes from Mum and Dad the good old-fashioned way.

I disagree. No-one who understands Dawkins properly thinks genes are immortal. The man himself explains, in The Ancestor's Tale, how someone can be your ancestor without your carrying a single one of his genes. Genes can be weeded out of the pool, or mutate unrecognizably.

And yes, meiosis and recombination (the good old-fashioned way referenced above) are not the only ways to transfer genes. Gene transfer may occur horizontally between individuals, even species. Gene expression (the way a gene builds a limb, say, or a habit) may be epigenetic, meaning it

is orchestrated by a set of chemical reactions that switch parts of the genome off and on at strategic times and locations. Source

But none of this explodes the selfish-gene metaphor; it merely extends the application. The genes are still selfish, the transfer and expression mechanisms are genetically evolved, and natural selection is still best understood at the level of the gene, not the organism.

I think the author of that opinion piece - clearly labelled as such, incidentally - is wrong. The only way in which she can be thought right is as follows: there are nongenetic factors that are also inherited, and these are also subject to natural selection. They needn't be genes, but they're still selected and - yes - they'll be selfish too.