Re: Haldane's Dilemma and quantitative genetics


"Bigfoot" <drforce2003@xxxxxxxxx> wrote in message news:e7rkol$2qkp$1@xxxxxxxxxxxxxxxxxxxxxx
Walter ReMine wrote:
Perplexed in Peoria wrote:
Though I suspect Walter is wrong both
about the limit (Walter makes it too low) ...

That misrepresents me. The "limit" is not mine, and I did not "make"
the limit (much less make it "too low"). The limit comes from Haldane,
and evolutionists never revealed its meaning to the general public. I
did.

I am sorry Walter this is one your most ridiculous statements. You have
only added more confusion to the issue and certainly no one has hidden
anything from the general public. The number of generations to the
fixation of a beneficial allele at a single locus is about 300
generations with a selection coefficient of .01 which you report
correctly. However, you have always misled the public into the idea
that two substitutions in a sexual species which act additively with
respect to fitness would require twice as long. This is false. It only
takes about 5-10% more generations for 2 substitutions than for 1. If
your concept of the cost requires twice as many generations for two
substiutions then maybe there is something wrong with the 'Remine Cost'
concept.

The 'Remine Cost' is the needless distraction and confusion factor
because it hides the fact multiple substitutions can go simultaneously
with only a slight increase in the number of generations required in
sexual species. This can be clearly shown with computer simulations and
has been. I have done it before but there was no need to publish
because A) you will claim it wrong because it came from an evolutionist
and B) Nunney has published similar simulations dealing directly with
Haldane's dilemma. showing that multiple substitutions in a sexual
species is different and clearly much larger numbers of substitutions
can occur than 1667. And of course now Malcom has taken his time to
write some simulations too to show a similar effect. But you don't like
his simulations either. Don't reply with your arm chair theorizing. Do
the simulations yourself or get someone to help you. If you can show
the effect then report it if not then atop perpetuating the 'Remine
Myth'.

The real limiting factor from these type of simulations shows the real
limiting factor is not Walters 'cost' but rather the rate of beneficial
mutations in populations.

You cannot blame the "limit" onto me.

Its time you stop making the same ridiculous claims over and over
again. The limit is for a single locus not multiple freely recombining
loci which act additively. You have milsed trhe public and continue to
obfuscate the issue. Of course if you actually did the simulations then
you might figure out Remine's Limit is Red Herring and not the stuff of
scientific revolutions.

Bigfoot, may I say respectfully that with friends like you, Darwin
doesn't need enemies. Your ignorance is appalling. You have apparently
not understood what Haldane has written, what ReMine has written, nor
what Nunney has written. You are a poster-boy example of the confusion
that ReMine claims has grown up around Haldane's Dilemma.

Where to start? Well, lets begin with Nunney's paper. It can be found
online here:
http://www.sekj.org/PDF/anz40-free/anz40-185.pdf
Nunney clearly understands, as you apparently don't, that the estimate
made by Haldane of 300 generations per substitution has nothing to do
with setting the selection coefficient to 0.01. The estimate is pretty
much independent of the selection coefficient. And it does not assume
that only one substitution is taking place at a time. Haldane clearly
contemplated multiple advantageous alleles proceeding to fixation at
any particular time. However, he suggested that progress toward fixation
by one allele would interfere with progress by another allele in that
both alleles 'compete' for a limiting resource - selective deaths.
Or, so said Haldane.

Now Haldane may well have been wrong in his estimates and in his theory.
Nunney points out that some of the assumptions that Haldane made are
unrealistic, in at least some circumstances. One such assumption made
by Haldane is that the population size is effectively infinite and that
unfavorable alleles are present in the population at the level set by
the mutation/selection balance. Hence, when the environment changes, and
a formerly slightly disadvantageous allele becomes advantageous, it is
already present in the population. No need to wait for a mutation to
get started. However, as Nunney points out, in a small population, there
is no selection/mutation balance. Those rare alleles that may be needed
to respond to environmental change are probably extinct. So, the population
must wait for a saving mutation, even before beginning to consider issues
of time to fixation and the cost of selection. At low population sizes,
the rate of substitution is limited by the rate of mutation - which becomes
a more stringent limit than the one Haldane and ReMine focus on. Nunney
demonstrates this in his simulation. And if you think that this point
refutes ReMine, then you are hopelessly confused.

Another point made by Nunney may be more significant. Nunney points out
that Haldane's logic ignores the possibility that density dependent
effects might modulate selection coefficients. If I am reading Nunney
correctly, he suggests that Fisher-Wright additivity of selection coefficients
might be correct in the low-density range - with each organism competing
against the environment. But in the high-density range, where each organism
tends to compete against other organisms, you might get something more like
truncation selection, and selection might become more efficient - advancing
more advantageous alleles with each selective death. It is an interesting
idea, and I think it has some validity. But I don't see that this suggestion
is really backed up by Nunney's simulations.


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