As far as I understand, a gene is just a portion of chromosome sufficiently small that it is unlikely to be split up during crossing over. (At least this is how Dawkins defins it). Roughly, a gene is then a sequence whose elements are one of 4 different molecules (g,c,a,t). A different sequence, or a shuffled sequence is then a different gene. Accidentally leaving out an element of the sequence or copying it twice (the sort of thing that happes on rare occasions during crossing over) creates a new gene.

Simon

The point is that there is a difference in the nature of mutations from crossing over and those from ionization induced disruption. Protein P53 addresses copying errors in normal somatic cell division. Genetic effects don’t actually involve taking copies of copies of copies endlessly like skin cells. Sometimes motion of DNA due to heat causes it to break, but the ends can be reconnected by P53. The ionization due to charged radiation causes more serious disruption than simple breakage.

The fact is, a woman has her genetic DNA in her eggs, which don’t get copied during her lifetime. So the main influence on those eggs are external factors like background radiation.

“selfish” in this context means only the following: those genes which act in a way that we might call selfish will be the ones that become more numerous in the gene pool. Nobody, including Dawkins, is suggesting genes have a brain or a purpose or any sort of long-term goal. Attributing human motives to them is merely a metaphor which aids our thinking (though as often as not confuses people).

The concept of selfish genes has become the orthodoxy in biology, after being introduced by dawkins in the seventies. That doesn’t mean you aren’t free to reject it of course, but make sure you understand it first. I repeat: nobody is claiming genes have any sort of goal or purpose. They are just bits of the DNA!

Note that cosmic radiation cannot considered to be the unit of evolution, because it does not self-replicate.

“In place of explaining this fuel for evolution, Dawkin’s chooses instead to describe the gene as surviving by being copied. That’s not evolution. All that can produce is selections from the original gene pool, hybrids and cross-breeds. Evolution of new species is driven by disruption to DNA, not it’s selfishness and preservation.”

Again, I’m not a biologist, but as far as I know the above is just false. The errors that occur during crossing over can include portions of the chromosome accidentally being copied multiple times, or perhaps left out alltogether. Probably much else is possible as well – that’s just the stuff I know about. I believe the above occur far more frequently than radiation induced mutations. Bear in mind that you might receive a lot of radiation over a lifetime, but it’s only one cell that gets passed on to your child.

Have you read Dawkins’ more recent ‘The Ancestor’s Tale’? It has a nice discussion of recent research on so-called ‘Hox genes’ which drove home to me that the above-mentioned copying errors really are sufficient to pruduce new species.

Simon

It’s a rephrasing of natural selection, which is the key non-random part of evolution. Obviously mutations play a part in evolution, and it is hardly “ignored” in his book. His illustrations in the book are constantly imagining some new gene popping up in a gene pool, and then thinking about its affects.

I’m aware of the disputes about evolution between Dawkins and Gould, and if you think Gould’s vision is closer to reality, that’s fine. I just thought it was over-the-top to say “…anyone scientific must utterly reject Dawkin’s selfish gene concept…”.