The Heresy Thread -- Where is Dawkins wrong?

[lucaspa]

The strange thing is that gene was chosen when nucleotides are the obvious most basic unit of selection.

Sorry, but nucleotides are not the basic unit of selection. Neither is the gene. Instead the basic unit of selection is the package of genes that is the individual. It is the individual that has to compete, not the gene.

 

This becomes even more apparent when we remember that most traits involve several genes and that most genes are involved in more than 1 trait. The single gene -- single trait is good illustration because it is simple, not because it is common.

 

A single nucleotide doesn't even correspond to an amino acid. Instead, it takes 3 nucleotides to code for an amino acid. And the 3rd nucleotide is often irrelevant. So how can selection be on the nucleotide level when selection can't even see the 3rd nucleotide in a codon because any nucleotide there is going to give the same amino acid?

 

And remember, most SNPs (single nucleotide polymorphisms) are very much neutral. You can see this doing a search on SNPs in PubMed.

[lucaspa]

How do you explain the fact that mothers are willing to die for their offspring? If it was really down to the organism, it would value its own life more than anyone else’s.

Altruism is explained on passing along the genes. But the SELECTION still occurs at the individual level. It is the individual that has those alleles that is going to have the behavior.

 

If a gazelle is eaten by a lion, it is the genes that are responsible.

But it is the TOTALITY of genes present in the gazelle, not just one. Remember, gene selection means that the single genes are being selected. That's not the case. In this case the gazelle can avoid the lion by several different mechanisms: early detection of the lion by better eyesight or hearing, agility, or straight out speed on a straight line. So, a gazelle that has the allele(s) for faster speed but the allele(s) for better detection is still going to avoid being eaten. Which gene(s) are selected? Or even, the gazelle with allele(s) for slower speed but better detection is going to avoid being eaten. So which gene(s) are being selected? Both.

 

It is because of the cooperative effort of genes in an individual that ensures that it is the individual that is selected, just like it was the team (individual in that competition) that was selected in the game, not Maradonna. No matter how good Maradonna was, if the team was bad, then Maradonna would not make it past that game to go further in the World Cup, would he?

 

But even organisms that were better at reproducing, would spread over organisms that were capable of surviving the asteroid strike.

That was a poor analogy. Any allele that confers an advantage or disadvantage after reproduction is essentially unseen by selection. This is why humans have so many degenerative diseases like blocked coronary arteries. Since heart attacks happen in the 50s or 60s, the individuals have already had their kids, so mutations to lessen heart attacks are not selective.

 

A current hypothesis on longevity in humans is the care given by grandmothers to babies. A child with a living grandmother to help care for it is more likely to live than a child without a second caregiver in a primitive society. So there is indirect selection for longevity in females (males just go along for the ride since the alleles are not sex-linked).

[lucaspa]

I think the confusion that the gene is the unit of selection is because population geneticists look at the change in frequence of alleles in a population. The change in frequence of the gene is the result of selection on individual organisms. Since an increased or decreased frequency of the gene was the result of selection, Dawkins understandably, but erroneously, decided that the gene was the unit of selection.