Moorad,
I think there is much less room for phenotypic variation in this case.
Usually in such an experiment one plates bacteria onto a media and picks
bacteria from a single colony. It seems safe to assume that all the
bacteria in that colony came from a single bacteria. One then grows
bacteria from that single colony up in some liquid media and then plates
out several billion bacteria onto a different media (in this case higher
salt concentration). Only a few of the millions/billions of bacteria may
manage to survive. Since these bacteria all came from a single bacteria at
one point we are definitely dealing with the "same bacteria." Rather than
selection on a bell shape curve of characteristics due to inherent
variation, it is more likely that the ability to survive on the salt media
is due to a point mutation of some type that enables the bacteria to
acquire an enhanced ability to deal with a high salt environment. Hope
that helps.
Joel
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I am not shamelessly promoting myself on the web in an effort
find a job :-). Please see my web page for my expanded CV.
,-~~-.___.
Joel and Dawn Duff / | ' \ Spell Check?
Carbondale IL 62901 ( ) 0
e-mail: duff@siu.edu \_/-, ,----'
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or nickrent-lab@siu.edu / \-'~; /~~~(O)
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