Re: [asa] historical versus experimental sciences

From: Tim <>
Date: Sun Aug 16 2009 - 11:53:43 EDT

Interesting news about your friend.
Richard Lenski seems to be getting funding. He even got a MacArthur
Fellowship for his work on the Long-Term Evolution Experiment and his
lab has published quite a stack of papers describing the changes they've
observed and the mechanisms behind them.

Dan Hartl published a series of papers with Dan Dykhuizen about 15-20
years ago describing their enzymatic modeling of a sugar utilization
pathway and predicting how strains carrying mutations in the pathway
would compete in selective environments.

Viruses have also been studied as model systems in evolution (I can't
recall which groups worked on them - I haven't kept up on that
literature but Lenski has also done some work in this area).

As for what conditions would give positive results, my experience has
been that practically any condition in which a resource becomes limited
produces evolutionary change. That's why, for example, we routinely
froze newly isolated strains for storage -- If we let the strains go
through too many generations, they acquired different traits and
diverged from the original isolate. Sometimes this drift affected
experiments, particularly with experiments involving continuous culture.

Archea: There is working being done to 'optimize' enzymes from
extremophiles for industrial uses (Well, not just extremophiles). I
think others are trying to work out ways to maintain microbial
fermentation reactors. Again, the problem is creating conditions such
that the bugs perform the chemical processes we want them to do and not
drift & evolve down pathways that reduce the yields over time, requiring
a restart of the entire reactor.

T. Ikeda

David Clounch wrote:
> Bernie,
> I have a friend who is an evolutionary biologist who studies "the process".
> He grows micro-organisms (my guess is e-coli because it has a 20 minute
> reproductive cycle) by the trillions under highly selective pressure. Last
> time I looked (and I may not remember this correctly) he had one experiment
> that had the equivalent of 60,000 years of evolutionary history. But that
> was 5 years ago. I don't know where it stands today. But....
> Guess what? He cannot get funding. Why? Nobody wants him to look for
> evolution.
> To me this is a fascinating subject. It would turn me into a biologist if I
> could do this sort of thing with, say, archaea in a boilng pot.
> But politics overrides EVERYTHING. His colleagues don't want to know what
> conditions would give positive results. They say they already know. But
> *they* can't produce the results in the lab. And they don't know why they
> can't. And they don't want him to find out why. Is this a form of proof by
> ignorance? If engineers operated this way people would be getting killed by
> bridges falling down (oh...wait...that actually happened on I35W, didnt it?)
> So Cameron rightly asks the questions he does about mechanism.
> -Dave

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Received on Sun Aug 16 11:54:44 2009

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