Friday, 7 December 2012

Group Selection? No way in Biological Hell!

Only recently I became aware of the fight that occurred earlier this year between two of my heroes: Edward O. Wilson and Richard Dawkins. Wilson at 84 (!) years published yet another book entitled "The Social Conquest of Earth" that, besides the sociobiology of ants, bees and termites, deals with the sociobiology of man. Wilson used to be an advocate of kin selection whereas Dawkins is the advocate of gene selection. According to the review that Dawkins wrote in Prospect (See here), Wilson finally has agreed kin selection can be explained by gene selection and now steps into the trap of Richards enemy number one: group selection. Now that is interesting to me since Dawkins refutes group selection religiously and I want to at least study what group selection might have to offer for what I refer to as "Darwinian Ascension". Maybe Dawkins would initially see this as a kick in his crotch so let me be clarify a bit: My interest in group selection regards Cultural rather than Biological Evolution. Can we ascend the power of our genes by using our memes? I believe Dawkins might share my interest.
So what is this row about? Pwf, that is not so easy to explain since it involves a lot of detail. See also the seemingly endless discussion that follows Dawkins' review and Wilsons' reply. It has some interesting details but it quickly ends in a discussion regarding memes rather than group selection in Biological Evolution, the point Wilson wants to make in his book. Unfortunately it does mean that this particular blog contains a lot of jargon, which I would normally explain but which in this case would interfere with the blog itself. I will however put some links for background information.
Basically, Dawkins, although in my opinion correct, has put himself in an awkward situation with his book "The Selfish Gene". There he lay the basis for his theory that, to put it simply, states that the only real unit of selection is the gene since the gene is the only entity that really replicates itself. Why does that put Dawkins in an awkward situation? Because it is a very reductionist position and most people hate reductionism since they do not clearly understand it and there is still a lot of Greedy Reductionism. It is easy just to skip a few facts. Furthermore the fact that a reduccionist believes he can reduce everything does not mean he can do it today. It is just a "belief" that in the end there is no real reason to come up with something additional, a Deus ex Machina or a Skyhook. And that is exactly the point of Dawkins. Gene selection CAN explain for all other apparent levels of selection such as the individual, the family (kin) and the group. So why come up with a Skyhook such as Groups Selection? You might argue that asexual organisms also replicate itself, hence reduction to the gene is not always feasible. Here I argue that sex, although extremely costly (you need to maintain half of your genetic material apparently for no reason), is the winning emergent property of evolution that allows for flexibility. Please do take into account that it is not the strongest, fastest or tallest organism that wins the struggle for existence, it is the one that can adapt. For this reason we have sex. Asexual organisms likely obtain certain levels to adapt by allowing for high levels of horizontal gene transfer and higher rates of mutation. Recent molecular evolution theories regarding early evolution describe a communal evolution of genes. Microorganims (read asexual organisms) share their genes by means of horizontal gene transfer, a mode of living guided by the optimization of the genetic code (See for instance PNAS 103:10696 or or TIBS 24:241). Hence, again the only entity that really replicates itself is the gene so only the gene can be subject of selection.
In "The Selfish Gene" and some of his follow-up books such as "The Extended Phenotype", Richard makes really clear that his theory is conceptually very strong. To me it is all just so obvious that I do not easily understand why people do not see the point, which unfortunately happens too often. The point is: You can explain ALL aspects of Evolution with a gene centered view but not the other way around. So why stick to other theories? I do not state we should discard them, it is just that there is no evidence NOR are there indications. But I do keep it in mind. Look at what happened to Lamarcks' theory of inheritance of acquired characters. Until a number of years ago the theory was seen as utterly ridiculous but has clearly revived on the basis op epigenetics.
The only answer I have in order to explain the resilience of many scientists against the gene-centered vision, is that there has to be something else that makes life. Where does the spark of life come from? Obviously not just a valid question, no I would concur with Shakespeare, albeit with a slight twist: "To be or not to be, that is the question". I say: Somehow complexity makes the Spark of Life and it is the job of Scientists to find out how. Others say it is God and the majority of people with a proper education in Science will say "We will, most likely, never find out". So in the end this is about where do you stand in life: Are you religious, agnostic or atheist. Needless to say that Dawkins is an Atheist and Wilson an Agnostic. Just to clarify: I do not mean to reduce any argument or discussion to the indicated level of "Where do you stand in life", I only want to indicate that it might very well have a strong influence in the way people, among which you and me, think. Are these Memes?
Back to the battlefield. Basically, it deals with the apparent incapacity of Hamiltons' rule in explaining a number of aspects in Evolution. Wilson, backed up by two very capable biological Mathematicians, explained in a Nature paper in 2010 (Free access paper provided by NIH), that Hamiltons' rule CANnot explain for it all. Not being a Mathematician, I understood the paper such as in "Math can only give you the correct answer as far as the model is correct but on the other hand the model can only give you the correct answer as far as the data are correct". Problem here is likely our understanding of the term "fitness". Can we really calculate the fitness a gene has for an individual, or worse for a group? Most certainly not. Hence I always understood Hamiltons' rule as a conceptual one rather than believing I can use the formula with accuracy. A similar thing has happened to Wrights' connected theories of fitness landscapes and shifting balance. Fisher always came with calculations and claimed that populations were actually quite big. But that is so beside the point Wright wanted to make: Wright made it conceptually plausible to arrive at a higher fitness peak, even when that means passing through a fitness valley. He even clarified that effective population size determines whether the process will actually occur or not. But as fitness, effective population size is virtually impossible to calculate. The same goes for Hamiltons' rule. It is very unlikely that math will really demonstrate who is right since calculating fitness is a sheer impossibility. Moreover, what really strikes me most is that people that fear reductionism, have such problems with conceptual explanations and go for a kill by means of mathematics, reductionism to the max. Group selection as an independent mechanism does not make any biological sense since there will always be one to exploit the situation rendering the "evolutionary strategy" instable. And I still have not heard one decent argument against gene selection. And NO, too reductionist is a terrible argument, gene selection is not gene centered: As if the theory does not take the environment into account. A good gene does well in a certain environment, that is actually the core of Dawkins' thinking.
Then am I sure there is no thing such as group Selection? That is like asking: Are you sure there is no teapot orbiting the sun somewhere (Russell)? Of course I am not sure but providing "mathematical evidence" for your belief that there is more than just gene selection is simply not the scientific way. Explain me why, how and what is the reason for the phenomenon. Let's put it differently. The concept of a meme is derived from a gene. Memes are subject to group selection, although it is often broken. The difference here is that it will not have a large impact on fitness. Hence, actually we all know that group selection is likely to occur also at a biological level BUT that the impact on an evolutionary timescale will be very limited. My belief is that group selection requires a force or reason to become established. In cultural evolution that would be intellect and free will. So show me the force that might drive group selection at a biological level and I will take it seriously.

May the force be with you!

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