SETI bioastro: Selfish Gene Theory Of Evolution Called Fatally Flawed

From: Larry Klaes (lklaes@bbn.com)
Date: Tue Apr 25 2000 - 11:55:54 PDT


http://unisci.com/stories/20002/0425001.htm

Selfish Gene Theory Of Evolution Called Fatally Flawed

The "selfish gene" theory proposed by Richard Dawkins has been an
influential thread in scientific and popular thinking for the past
25 years. The key concept is that any action is a supremely self-
serving one on the part of the actor, devoid of motivation to serve
the larger group to which the actor belongs (i.e., genes as parts
of an organism).

As far as Dawkins is concerned, the struggle for survival always
takes place at the scale of the individual gene. Instead of thinking
that organisms compete, Dawkins would have us think that different
versions of the gene, known as alleles, compete.

(The reason we shouldn't think about organisms as competing is that
we would then have to think about genes that are part of the same
organism as cooperating -- which, according to Dawkins, genes don't
really do.)

The "selfish gene" perspective has not gone unchallenged. Among others,
the well-known evolutionary biologist Richard Lewontin and philosopher
Elliott Sober have raised specific objections to this focus on the gene.

The debate remains unresolved because the gene-centered view is,
demonstrably, partially valid.

Having difficulty figuring out when it works and when it doesn't,
some scientists carried the argument over into the political/
philosophical realm:

Arguments about the gene-centered view often focused on whether people
should believe that altruism exists at all.

In the current issue of Advances in Complex Systems (February-April), Dr.
Yaneer Bar-Yam, president of the New England Complex Systems Institute
and an expert on the application of mathematical analysis to complex
systems, contends that the selfish-gene theory of evolution is fatally
flawed.

If his mathematical proof gains general acceptance, it will shut the
door on controversial "gene-centered" views of evolution.

Bar-Yam, in the upcoming article, proves that the "selfish gene"
approach is not valid in the general case. He demonstrates that the
gene-centered view, expressed in mathematical form, is only an
approximation of the dynamics actually at work.

And this approximation does not always work. Specifically, it breaks
down when a process called symmetry breaking enters the picture.
Symmetry breaking is a concept borrowed from physics. It corresponds,
in evolution, to trait divergence of subpopulations.

In this view, genes relate to each other differently than theory would
predict when the organisms to which they belong are themselves components
of groups that are at least partially distinct, one from another.

The key to Bar-Yam's analysis lies in recognizing three levels of
structure in nature: the gene, the organism and the group (or network)
of organisms.

According to Dr. Bar-Yam, the effective evolutionary fitness of each
allele depends on the distribution of alleles in the population.
Thus, the fitness of an allele is coupled to the evolution of other
alleles.

The self-selecting process predicted by the selfish-gene model becomes
quickly skewed when correlations in reproduction exist which give rise
to less than complete mixing of alleles in the gene pool. This may occur
through several mechanisms, including mate selection and partial
geographic isolation.

The gene-centered view, Dr. Bar-Yam points out, can be applied directly
only to populations in which sexual reproduction causes complete allelic
mixing. (Such populations are called "panmictic" in biology.)

Many organisms are part of populations that do not satisfy this condition.
Thus, the gene-centered view and the concept of the "selfish gene" does
not describe the dynamics of evolution, Dr. Bar-Yam concludes.

(Editor's Note: This story is based on a brief release submitted by David
R. Efros of the New England Complex Systems Institute.)

[Contact: Dr. Yaneer Bar-Yam]

25-Apr-2000



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