Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!utgpu!water!watnot!watmath!clyde!rutgers!lll-lcc!pyramid!prls!mips!rmg
From: rmg@mips.UUCP
Newsgroups: sci.bio
Subject: Re: No Limits to Growth
Message-ID: <228@quacky.mips.UUCP>
Date: Thu, 26-Mar-87 11:48:55 EST
Article-I.D.: quacky.228
Posted: Thu Mar 26 11:48:55 1987
Date-Received: Sat, 28-Mar-87 04:19:32 EST
References: <120300015@inmet> <513@cpocd2.UUCP> <1866@k.cc.purdue.edu> <533@cpocd2.UUCP>
Reply-To: rmg@quacky.UUCP (Richard M. Geiger)
Organization: MIPS Computer Systems, Sunnyvale, CA
Lines: 40
Keywords: monoclonal species

In article <533@cpocd2.UUCP> howard@cpocd2.UUCP (Howard A. Landman) writes:
...
>Now, to represent an
>entire species, you need 2 or 3 or 4 orders of magnitude more than that,
>because genetic diversity is important to allow a species to adapt.

To pick at a couple of nits:

I wonder about the "need N orders of magnitude more" genetic information.

I've recently read about at least one species (a lizard in the S.W. U.S., if
I recall correctly) for which all members are a single clone; they reproduce
asexually (though they *do* have the funny habit of exhibiting sexual
behavior- individuals trade off the roles of mountor and mountee
periodically). I can find the reference if anybody wants it.

Also, I believe we can find many cases of species for which the number of
individuals has dipped to well below 1000 and then recovered; even
disregarding the redundancy in genetic information in any two individuals
(how much redundancy is this, by the way?), you would need 10,000
individuals for 4 orders of magnitude more diversity. It doesn't seem that
that many are actually required.

[After a bit more thought, the question of "what *is* redundancy in genetic
information" gets pretty interesting. I've heard the statement that Humans
and chimps share something like 98% common genetic information. I guess the
key is what you take to be the smallest unit of information you are
comparing. I guess it's the "gene", which I understand to be a subsequence
of base pairs within a DNA strand... but at this point, my understanding
starts to get clouded.]

In any case, I have to agree that we should be careful about wiping out
species. Even if we get real clever about how all of this genetic and
molecular biology business works, and can more or less engineer this stuff
at will, even from scratch(!)- we would still be left with the immensely
trickier problem of deciding wisely *what* to build.
-- 
- Rich Geiger
{decvax,ucbvax,ihnp4}!decwrl!mips!rmg
MIPS Computer Systems, 930 E. Arques Ave., Sunnyvale, CA 94086  (408) 720-1700