-----Original Message-----
From: Jayme Blaschke <[EMAIL PROTECTED]>
To: [EMAIL PROTECTED] <[EMAIL PROTECTED]>
Date: Thursday, February 22, 2001 10:41 AM
Subject: Re: Microoganisms and Phylogeny
>
>>>>In my ignorance, I seem to be missing something. Talking about the "risk
of
>cross-pollination": risk of what? "We are going to have to be very
careful."
>Careful of what? If Martian microbes contaminate Earth microbes or vice
>versa, what might happen? Please help a layman understand. Thanks.
>
>
>Nothing might happen. Or, we could get events like that which sometimes
happen in hospitals and such, in which a drug resistant bacteria abruptly
swaps genes with that of another that has never shown resistance and we
suddenly have an outbreak. Or the concern that pollinating crops
gene-spliced to be naturally toxic to certain insects will pass this on to
wild cousins (re: weeds) which will then run rampant without nature's checks
and balances (re: bugs eating them) to control things.
>
>Granted, these are terrestrial analogies, but the concerns can be
extrapolated to space-originating organisms. The Andromeda Strain can be
viewed in much the same light, although no gene-swapping takes place there
(although gene swapping DOES take place in the movie Species -- there's a
cautionary first contact tale that casts Contact in a new light). But
again, unless Earth or Mars "seeded" each other, the possibility of
cross-pollination is astronomically low.
>
Well, we certainly don't need to worry about gene-swapping among macroscopic
organisms -- Star Trek to the contrary, it just doesn't happen.
Gene-swapping DOES happen very frequently among bacteria -- which has
tangled up the early part of the DNA evolutionary tree to the point that we
probably never will be able to figure out the genetic nature of the earliest
Earth microbes -- but, as far as I'm concerned, it would be only one very
minor part of the overall biocontamination problem from alien microbes; my
overall concern would be simply that they might find some part of Earth's
environment to their liking and turn into more or less serious pests.
Bruce Moomaw
==
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