[asa] Reducible design and less reducible design

From: David Campbell <pleuronaia@gmail.com>
Date: Wed Sep 16 2009 - 12:01:32 EDT

In the current PNAS, there is an article on the evolution of a complex
molecular system in the mitochondria:

Abigail Clementsa, Dejan Bursaca, Xenia Gatsos, Andrew J. Perry,
Srgjan Civciristov, Nermin Celik, Vladimir A. Likic, Sebastian Poggio,
Christine Jacobs-Wagner, Richard A. Strugnell and Trevor Lithgow
The reducible complexity of a mitochondrial molecular machine
PNAS September 15, 2009 vol. 106 no. 37 15791-15795

Abstract: Molecular machines drive essential biological processes,
with the component parts of these machines each contributing a partial
function or structural element. Mitochondria are organelles of
eukaryotic cells, and depend for their biogenesis on a set of
molecular machines for protein transport. How these molecular machines
evolved is a fundamental question. Mitochondria were derived from an
α-proteobacterial endosymbiont, and we identified in α-proteobacteria
the component parts of a mitochondrial protein transport machine. In
bacteria, the components are found in the inner membrane,
topologically equivalent to the mitochondrial proteins. Although the
bacterial proteins function in simple assemblies, relatively little
mutation would be required to convert them to function as a protein
transport machine. This analysis of protein transport provides a
blueprint for the evolution of cellular machinery in general.

Apparently they were unable to reduce the complexity of the author list.

More generally, there is a perfectly good mechanism to evolve complex
molecular systems-natural selection working on the genome. ID
advocates generally claim that the probabilities are very low, but the
fact remains that, in principle, it can be done.

Another recent article (Donald I. Williamson, Caterpillars evolved
from onychophorans by hybridogenesis PNAS published online before
print August 28, 2009, doi:10.1073/pnas.0908357106) speaks of
"Darwinian" rather in the manner of much ID: "I reject the Darwinian
assumption that larvae and their adults evolved from a single common
ancestor. " Here "Darwinian" seems to mean "following a
non-reticulating evolutionary path". As caterpillar-like larvae
actually have a number of features characteristic of true arthropods,
different from onychophorans, I'm highly dubious that Williamson's
idea will hold up, though it is true that as far as I know we don't
have the detailed genomic data on onychophorans necessary to totally
disprove it.

I would advocate, as a better example of design, the recent finding
that you get more antioxidants out of your tea when it has sugar and
ascorbic acid in it-obvious divine guidance on the right way to make
it. The study seems not to have checked on the role of ice.
Seriously, this ties into the general question of aesthetics as
evidence of design-beauty, wonder, etc. As omnivores we may be
expected to be able to consume many different things, but appreciating
complex artificial combinations, typically incorporating plant toxins,
often from multiple continents, seems curious. (Unless it's derived
from ripe fruit or is something the plant would use itself such as
sugar or starch, most plant-derived chemicals are intended by the
plant to discourage other things from eating it. This would include
the key components to most herbs and spices, as well as caffeine,
theobromine, etc.)

Dr. David Campbell
425 Scientific Collections
University of Alabama
"I think of my happy condition, surrounded by acres of clams"
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Received on Wed Sep 16 12:02:05 2009

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