***** Continued From Previous Message *****
rving traits across species doesn't
> make sense.

JE:-
Waddington demonstrated that such a buffer exists.
What is missing is a testable explanation.
The explanation must fit nature, nature does
not have to fit the explanation! However
Stalin and Hitler would attempt to force
nature to fit their "theories" by shooting
anybody who disagreed.

> MR:-
> The authors state, "Canalization is then a byproduct, and
> the release of hidden genetic variation is caused not by disruption of
> adaptive buffering mechanisms that evolved to conceal the genetic
> variation that is released, but by reduction in the complexity of
> regulatory networks that evolved to prevent the expression of lethal
> mutants. Why would a reduction in the complexity of regulatory networks
> that evolved to prevent the expression of lethal mutants result in the
> release of hidden genetic variation?


JE:-
Because the hidden information
was multiplicative.


> MR:-
> The authors contradict themselves
> when they write, " Such selection evolves robustness against not only
> lethal mutations but also, as an unselected byproduct, against mutations
> of smaller effect that produce quantitative variation. It does so by
> causing networks of interacting transcriptional regulators to increase
> in complexity. Thus, more highly connected networks may be more
> canalized not because canalization of quantitative variation has been
> selected but because complexity in the underlying developmental network
> has been selected to suppress the effects of lethal disruptions of gene
> expression.

JE:-
The sentence: "It does so by causing networks of interacting
transcriptional regulators to increase in complexity" refers
to multiplicative and not just additive networks where information
increases in a _geometric_ way.

Regards,

John Edser
Independent Researcher

PO Box 266
Church Pt
NSW 2105
Australia

edser{at}tpg.com.au
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