Individual vs Gene selection.

[Dymanic]

Originally posted by Art Vandelay

I can see how, when evolutionists abstract evolutionary phenomena, they would categorize this as selection for the other gene, but there seems to be an undercurrent of "the gene is cheating". No gene acts in a vacuum; any attempt to "give credit" to the gene "truly responsible" for the selection will eventually bog down in arbitrary determinations.

Well said. Evolutionary biology is filthy with arbitrary determinations. That's part of what makes it fun. Have we talked about the definition of 'species'? The whole business has a way of grading off into philosophy.

When all is said and done, the only truly objective standard, and the only one that matters in the grand scheme of things, is that a gene is selected to the extent that its representation is increased in the gene pool.

But representation in the gene pool is also influenced by factors other than selection. There is debate over the importance of drift; some have gone so far as to propose that it is more influential than selection.

The "fitness" of the gene includes everything that allows it propogate, including resistance to mutation, tendency to arise from mutations of other genes, association with other genes, meteors that hit several individuals carrying competeting genes, etc.

I think that is stretching the concept of 'fitness' a bit too far, especially the bit about meteors -- but it is important to note that plain 'ol dumb luck also plays a significant part in evolution; it's just as likely to be survival of the luckiest as survival of the 'fittest'.

Edited to add: Let me rephrase that last. 'Fittest' might be thought of as: "The one most likely to get lucky".

 

[Dymanic]

and to get back to this

Originally posted by Dylab

Wouldn't the altruistic gene example also be an example of group selection? How is it different?

This gets hairy.

Let's assume the gene as the unit of selection, and consider altruism as an item on a list of genes for various attributes like big ears, sharp teeth, and long legs. Each gene will prosper in a certain environment, an environment which includes the presence (or absence) of other genes. You can't just select a single item from the list and say: "This is an adaptive trait" without taking into consideration the genetic environment in which that gene exists -- any more than you can point to a single organism and say: "This is a well-adapted organism" without taking into consideration the physical (and possibly the social) environment in which that organism exists. Sharp teeth are great for a predator, but not so great for a grazing animal, etc. A gene for kin altruism wouldn't get much traction in an organism lacking an ability to make good guesses about his degree of relatedness to others in his group (unless typical group size were small enough to make relatedness a reasonable default assumption), and a gene for reciprocal altruism wouldn't get much traction in an organism lacking an ability to differentiate between co-operators and defectors.

If the environment favors altruistic behavior then, it is because it works for the individual gene, in a way that can be demonstrated mathematically. It would not be very surprising if such a thing produced, as a side-effect, a benefit to the group as well -- in fact, it is exactly what we would expect with small groups of closely related individuals -- but to start calling it 'group selection' seems like an intellectual indulgence; the addition of a redundant layer of explanation. That might be a useful abstraction in certain contexts, but I would say that a genuine group selection theory, to have any real power, would have to explain things which cannot be better explained at lower level. That would be cool. I'd love to see it. So much has to do with how you look at things though, and so far I haven't seen anything that objectively trumps gene-level theory. Wade's experiments on flour beetles are a good example.

 

[Peter Soderqvist]

That's right, Peter; they are complementary. But since the biology can't directly get at the genes, it has to work on the phenotype. It is "trying" to get at the genotype, but doesn't have the direct means to get there.

Soderqvist1: We can say that natural selection reach indirectly individual genes by selecting between individual phenotypes, or a gene's phenotypic reach out! In example; suppose if gene x is on a particular chromosomal loci has a higher probability to make say; a rabbit a faster runner than if some other competing gene is there, thus rabbit with this gene has a higher probability to pass his genetic trait into next generation than other genes has, because the slower running rabbits will probability end up as dinner for foxes, and so genes are selected! Richard Dawkins book; The Extended Phenotype, the long reach of the gene has pointed out that; a gaping chick is an extended phenotypic reach out to the "mother" to feed the chick!

The extended Phenotype, the long reach of the gene!
Chapter1: Rather, the replicator should be thought of as having extended phenotypic effects, consisting of all its effects on the world at large, not just its effects on the individual body in which it happens to be sitting.
http://www.world-of-dawkins.com/Dawkins/Work/Books/extend.shtml

Think about a beautiful woman with red lipstick on her pouting lips and suggesting you a kiss, if you have doubts about that pouting lips has impacts on the world!

 

[BillHoyt]

Soderqvist1: We can say that natural selection reach indirectly individual genes by selecting between individual phenotypes, or a gene's phenotypic reach out! In example; suppose if gene x is on a particular chromosomal loci has a higher probability to make say; a rabbit a faster runner than if some other competing gene is there, thus rabbit with this gene has a higher probability to pass his genetic trait into next generation than other genes has, because the slower running rabbits will probability end up as dinner for foxes, and so genes are selected! Richard Dawkins book; The Extended Phenotype, the long reach of the gene has pointed out that; a gaping chick is an extended phenotypic reach out to the "mother" to feed the chick!

I certainly agree with this view in principle, although it is more than a bit difficult to analyze mathematically.

 

[CBL4]

I think the debate been individual selection vs. gene selection is much ado about nothing. Strictly speaking, the genes are getting more or less common but that is not usually the way to look at it.

I consider thinking about things via gene selection sort of like trying to predict the action of a ball by looking at the all the subatomic particles. It is the most accurate method of looking at thing but just not very useful. Clearly this is a poor analogy because we can actually explain things such as altruism by gene selection. However, I think it is overused to predict behavior especially in humans.

I have read Dawkins and Gould on the subjects and I think they generally talk past each other instead of actually debating. Dawkins is “correct” but Gould’s view is generally more when talking about evolution in the large sense. As we learn more and more about genes and selection, the gene selection will become more and more useful for explaining specific results.

CBL

 

[Dymanic]

Originally posted by CBL4

I think the debate been individual selection vs. gene selection is much ado about nothing

I think the debate over whether or not the debate over individual selection vs gene selection is much ado about nothing is much ado about nothing. Or, maybe not.... actually, I can't decide.

...we can actually explain things such as altruism by gene selection. However, I think it is overused to predict behavior especially in humans.

Another possibility is that it is underused.

I have read Dawkins and Gould on the subjects and I think they generally talk past each other instead of actually debating. Dawkins is correct but Gould’s view is generally more when talking about evolution in the large sense.

I find the whole thing bizzare and confusing. Hard to tell the actual arguments from the strawmen. My viewpoint seems to flicker around a lot. It bugs me.