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Developmental Gene Regulatory Networks: the DNA Puppet Masters

October 22, 2016

from Darwin’s Doubt, by Stephen Meyer

Eric B. Nash :

dGRN (developmental gene regulatory networks) operate during high level embryonic development. This is referred to as epinenetic, meaning beyond genetic. I saw copies of these networks, like intricate sketches, by a researcher called Eric Davidson from Caltech, who did experiments on sea urchins. These networks with their timed sequencing functionality–like the exact iteration in cell division when a cell would be coded as, say, a posterior spine (in the case of a sea urchin)–and they were extremely complex, much like schematics one might see for circuits in electronics.

The interesting thing is that these high level embryonic developmental regulatory networks were shown to be beyond mere genes, mere DNA coding. There was a separate network that controlled (or orchestrated) early body-shaping processes. These networks used the coding in DNA, but the regulatory networks called out *when* that coding would be applied to the further development of a large group of cells.

Because networks are systems with knock-on effects downstream, mutations would have to be multiple and coordinated. This is why fruit fly experiments yielded deleterious effects. Sure, you can induce mutations and come up with all kinds of crazy body plans. But for beneficial mutations to occur–or limb-erasing ones, for that matter–mutations would have to be tweaked in a targeted way at multiple sites in the regulatory network *at the same time.* This kind of thing would be a very fine tune-up (or tune down in snakes’ cases). The probabilities are infinitesimally low.
(“The Origin of Body Plans” )

DGRN undoes neo-Darwinism.
Stephen J. Gould, the revered paleontologist from Harvard, came up with “punctuated equilibrium” based on the fossil record. Species would arise very quickly with a fully formed body plan and live millions of years basically unchanged, then disappear abruptly. Thing is, the quick appearance of new body plans defies any “small steps” explanation based purely on population genetics.

The likelihood of multiple coordinated mutations to the dGRN is impossibly low even once, and to believe that this kind of thing could happen tens of thousands of times such that a whale would come from a hippo is not evidence based; it’s faith pure and simple.
An anthology of articles came out in 2003 (?) in which different scientists challenged the neo-Darwinian explanation, and dGRN contributed to this. They called for new approaches to the riddle of speciation.
Interestingly, their commitment to scientific naturalism remained. They were esteemed highly enough that they could get away with issuing this challenge, but wouldn’t stray from the party line that evolution accounts for the diversity of life and natural history.
Eric B. NashThe above summary was drawn from chapter 13 (titled The Origin of Body Plans) of Darwin’s Doubt,
The next chapter is The Epigenetic Revolution. There’s a reference to an anthology of articles. Here’s the link to the anthology info:
https://mitpress.mit.edu/books/origination-organismal-form
Eric B. Nash “Why, for instance, did the basic body plans of nearly all metazoans arise within a relatively short time span, soon after the origin of multicellularity? Assuming that evolution is driven by incremental genetic change, should it not be moving at a slow, steady, and gradual pace? And why do similar morphological design solutions arise repeatedly in phylogenetically independent lineages that do not share the same molecular mechanisms and developmental systems? And why do building elements fixate into body plans that remain largely unchanged within a given phylogenetic lineage? And why and how are new elements occasionally introduced into an existing body plan?”

This is from ch.1 one of that anthology, which can be read at:
https://mitpress.mit.edu/…/9780262134194_sch_0001.pdf

Nancy Northrup As biologist Douglas Axe points out in his book Undeniable the Cambrian Explosion isn’t just a matter of the quick appearance of new body plans, it is also a massive increase in information that produced those body plans. That increase of information is not accounted for in the neo-darwinian myth.

And this: “But for beneficial mutations to occur, mutations would have to be tweaked in a targeted way at multiple sites in the regulatory network *at the same time.*

This kind of thing would be a very fine tune-up. The probabilities are infinitesimally low.” I believe the tweaking occurred at the quantum level because Life is Quantum: http://aeon.co/…/quantum-biology-the-uncanny-order-of…/

Life is quantum

Weird quantum effects are so delicate it seems they could only happen in a lab. How on Earth can life depend on them?

aeon.co|By Aeon
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