Date: Mon, 18 Mar 2002 20:26:29 -0700
From: maa32 
Subject: (urth) Instant Monsters

Here is one more interesting lecture that talks about the creation of instant 
species.  If you've had enough polyploidy, ignore it, but its terms are pretty 
cool.  It tells that polyploidy is the only way to create an instant monster 
or a new species!

"
'Instant Species' and Hopeful Monsters

Is it possible to create a new species instantaneously, in one fell swoop? 
This idea was very popular when Mendelian genetics were rediscovered and 
mutations were studied. But it turns out (not unexpectedly) that an organism 
is a highly complex whole in which many parts must cooperate. Large changes 
tend not to make such a complex whole better, but tend to completely spoil at 
least one complex part of the whole.

There is one clearly documented instance of 'instant speciation' which is very 
rare in animals, but common in plants:

Polyploidy (having more than 2 sets of chromosomes as in a normal diploid
individual).

     Individual: 2 sets of chromosomes (diploid)
     Sex cells; 1 set of chromosome (haploid)

Combination of individuals of different species (with different sets of 
chromosomes)
is not possible because the two different chromosomes can not pair up.

A can not pair with B, but if individuals have double sets of chromosomes, the
body-cells can be AABB, the sex cells AB. In reality, this occurs both with 
doubling chromosomes within a species, or by doubling genes during 
hybridization of two species. "



--