Model Organisms

Anthony J. Pelletier, Ph.D. anthonyp at scripps.edu
Fri Apr 25 12:55:45 EST 1997

In article <E95tH1.J64 at gpu.utcc.utoronto.ca>, lamoran at gpu.utcc.utoronto.ca
(L.A. Moran) wrote:

> Less so than before. But I've completely forgotten what we were discussing.
> If I recall correctly you mentioned that no one except Benzer had done a
> detailed analysis of mutations in a gene. I suggested that Miller's work
> on lacI might count. Is that the right topic?
> Larry Moran

That's an rather funny memory you have there.  I actually laughed out loud
when I read that.
No, I was talking about the exchange in which you took on a very pedantic
tone ("isn't science cool") while completely mis-attributing the work of
Sydney Brenner to Seymour Benzer.  

You responded to my reference to the leClerc paper (Science 274:1208) on
mut- strains by claiming that this paper showed:

     "One of the more virulent "new" strains also carried a mut mutation."

When in fact the paper showed that among the virulent strains:

1) Of initial  349 strains, 9, or 2.6% (not "one") were mut- strains.

2) among single-drug resistant colonies (those surviving the first selection)
approximately 32% were mut- strains.  That is, after one imposed
selection, the frequency of mut- increased 12-fold.  

3) among populations harboring large numbers of members resistant to each
of the three drugs, all, *100%*, were mut- strains.  

Perhaps by "one" you meant to refer to the fraction that were mut-?  That
is, a fraction of 1 equals 100%.
And finally, you claimed that it was impossible for a system to evolve in
which enhanced mutation provided a selective advantage to a changing
environment, and asked me to provide exmaples.  Then, you completely
ignored me when I posted several, claiming you were too busy.

That was the exchange I remember.

Anthony J. Pelletier, Ph.D.
Assistant Professor, Department of Cell Biology
The Scripps Research Institute
La Jolla, CA

anthonyp at scripps.edu

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