Congratulations to Sean

Sean Carroll (the physicist, not the developmental biologist) is moving on up to CalTech.

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Paul wrote:

"Sean Carroll (the physicist,..."

Speaking of Sean B. Carroll (the developmental biologist) you may have seen this...

Science 7 April 2006:
Vol. 312. no. 5770, pp. 97 - 101

Evolution of Hormone-Receptor Complexity by Molecular Exploitation
Jamie T. Bridgham, Sean M. Carroll, Joseph W. Thornton*

What the heck is Sean M. Carroll (the physicist) doing writing a paper on developmental biology?

Am I missing something or is this a huge typo? Or is there yet a third Sean Carroll afoot?

Mystery solved.

There is indeed a third Sean Carroll, Sean M. Carroll who is a graduate student in the Thornton Lab at UOregon. Jamie Bridgham is a post doc at the Thornton Lab. Both George Carroll and Scott Bridgham are tenured professors at UOregon. Perhaps these folks are related to their distinguished fathers?

Thanks, PZ. You wouldn't believe how many papers I get to referee from Cell, presumably meant for the other SC. That's okay, I reject them anyway.

Now to comment on the paper:

It begins:

"The ability of mutation, selection, and drift to generate elaborate, well-adapted phenotypes has been demonstrated theoretically (1, 2), by computer simulation (3, 4), in the laboratory (5, 6), and in the field (7). How evolutionary processes assemble complex systems that depend on specific interactions among the parts is less clear, however. Simultaneous emergence of more than one element by mutational processes is unlikely, so it is not apparent how selection can drive the evolution of any part or the system as a whole. Most molecular processes are regulated by specific interactions, so the lack of exemplars for the emergence of such systems represents an important gap in evolutionary knowledge. As Darwin stated, "If it could be demonstrated that any complex organ existed which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down"

Unfortunately, the paper contributes nothing that answers this daunting dilemma. There is absolutely no evidence presented that a neo-darwinian mechanism of random mutation and natural selection created the highly organized structures, processes and systems that are described. The only thing offered is "gene duplication" without any kind of empirical support for this view.
The authors state: "we characterized the functions of the ancestral corticoid receptor (AncCR)--the ancient protein from which GR and MR descend by gene duplication."
While there is sufficient evidence to conclude that these ancient proteins are related to each other and possibly originated from common origins, there is no hint of the mechanism by which this may have occurred.
This is the most important question, the mechanism. That these systems are closely related, there can be no doubt, that they emerged from a common origin similarly, though not as well supported, does not elicit great concern. That they are the product of random mutation, natural selection, genetic drift or chromosome duplication is highly questionable and unlikely.
The more likely scenario is that all of the information that led to the evolution of these structures, processes and systems was already present in the genome from the beginning and what we view as evolution is not the result of random, accidental or non-directed processes, but the unfolding of a carefully planned series of steps that were programmed into the genome at the time of its first arrival on earth.
Noah's ark, so to speak. Not a wooden boat filled with actual animals, but a seed (or seeds) planted on the earth in the form of DNA that took root on a fertile, water body and evolved into the complexity and diversity we see today.

"Life comes from space because life comes from life."

"Caltech", not "CalTech"! I mean, come on, I agree with you, PZ, way too often, so at least I can be a nitpicky little bastard :)

Dave Bacon is right: The cognoscenti do not use interior capitalization in "Caltech".

As for the multiplicity of Sean Carrolls, why are all of them distinguished science types? Lucky dogs! The guy who shares my real name is a registered sex offender in the next town over (he doesn't even have the good grace to live in another state). Damn. At least he's not a fellow Caltech alumnus.

So they loaded up the truck and moved to Beverly.
Hills, that is.
Swimmin' pools, movie stars.

The guy who shares my real name is a PORNSTAR for crying out loud. The first time I googled myself, I almost died from laughing. My mother was less pleased.

By vandalhooch (not verified) on 08 Apr 2006 #permalink