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From: mrh@cybvax0.UUCP (Mike Huybensz)
Newsgroups: net.origins
Subject: Re: Bacteria
Message-ID: <490@cybvax0.UUCP>
Date: Mon, 22-Apr-85 18:34:05 EST
Article-I.D.: cybvax0.490
Posted: Mon Apr 22 18:34:05 1985
Date-Received: Thu, 25-Apr-85 08:17:31 EST
References: <947@uwmacc.UUCP>
Reply-To: mrh@cybvax0.UUCP (Mike Huybensz)
Distribution: net
Organization: Cybermation, Inc., Cambridge, MA
Lines: 42
Summary: 

In article <947@uwmacc.UUCP> dubois@uwmacc.UUCP (Paul DuBois) writes:
> Well.  Ray Miller posted an article containing a report on a newspaper
> story (from Pravda).  It was quickly and roundly rejected as irrelevant,
> as Pravda is a newspaper and not a scientific journal.  Ok, fine.  (Not
> really, but for the sake of argument.)  Now we have a report on a story
> in the "Atlanta Constitution".
> 
> Does the same logic apply?

Yup.  It isn't necessary to hypothesize evolution of a new enzyme.

> But let us accept the above article at face value.  It is stated that
> the bacteria recently have evolved enzumes that allow them to
> matabolize man-made plastics, and that the discoverer of the bacteria
> feels this may be evidence of rapidly occurring evolution.

Anybody who has studied bacteria much can tell you that new bacteria are
a dime a dozen.  Alternatively, genes from other bacteria may have been
transported by phages into the new ones.

> I guess the real question is whether the enzyme was present in 1972 or
> not.  What does 'recently evolved' mean?  1985? or 1972?  If 1972,
> then nothing has been shown, because one cannot say that the enzyme
> wasn't present before (or that it was, of course), and in that case
> the claim falls to the ground.

What evidence is there that this bacterium recently evolved.

> If it CAN be shown, then what sort of evolution does this constitute?
> For example, is it substantially different than, say, production of a
> "new" antibody in response to immunization?

If this is indeed evolution, it could represent relocation of genome fragments
between species by phages, or through sex.  Or it could represent repeated
alteration of a precurser enzyme to a more efficient form.

But this would all be a form of microevolution: changes within a population,
rather than speciation.  (The question of what composes a bacterial species
is a darn good one....)
-- 

Mike Huybensz		...decvax!genrad!mit-eddie!cybvax0!mrh