Partial Response to Rogers July 31

Paul Cockshott wpc at clyder.gn.apc.org
Tue Aug 1 15:15:24 MDT 1995


I find Carol Coxes contributions on the concept of the
individual persuasive. But even on the terrain of
modern Darwinism I remain unconvinced by Lisa's arguments.

Lisa wrote:
-----------
There are good reasons for many different genes to work together very
well when they find themselves stuck in a body together.  ....
Any one gene that can't work
with the others can ruin the whole project, killing itself along with
all the rest (one individual dies.)  All the genes [in the nuclear
DNA] within an individual are in the same boat, they sink or swim
together.  This means that each one's reproductive interests are
identical to the others'!  No wonder they all pull together, because
no one gene can reproduce alone.

Paul
----
Is it really true to say that the genes are within an
individual?

An individual may contain copies of the genes, but excepting
new mutations, there will be many copies of each gene around
in the population. Any one given gene thus simultaneously
co-exists with multiple other combinations of genes.

Your argument is that in a given individual they must all pull
together if they are to survive and thus that the individual
is a valid unit of selection. If we were to generalise this
however we would be back to arguing that the species is a unit
of selection, since, the same argument must apply to all individuals
and thus all gene combinations. You almost go on to say this:

Lisa:
-----

Therefore, each gene must be able to work within each new combination
or else the new individual will not make it.  From this we get a view
of the "gene pool" as a group of co-evolved genes.

Paul
----
You say here co-evolved, but the implication is that all of the
genes in the gene pool work together. Which would imply that
the argument for individual self interest could be extended to
population self interest.

I think there must thus be some fault with your original argument
for biological 'self interest'. It lies, I think, in the idea that
the genes in an individual must always work together. Consider the
following situation.

There exist two genetic locations each with two alleles A, A' and
B, B'. Assume that population frequencies are:

A   50%
A'  50%

B   90%
B'  10%

Assume that combinations AB and AB' are reproductively neutral, which
we will characterise as a reproduction probability of 100%.
But let us assume that A'B has a positive reproductive advantage of
11% but the combination A'B' has a negative reproductive advantage
of 50% - i.e. has a 50% chance of preventing the production of
offspring.

The result is an equilibrium mixture ( within the accuracy of
my back of the envelope calculations ).

Thus it is quite possible for the combination of genes in an
individual to fail to work together if this is compensated for
by other advantageous combinations. Thus your original argument
for the individual as a selective focus is thrown into question.



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