🚀 go-pugleaf

> janw@inmet.UUCP (Jan Wasilewsky)
> Cross-breeding creates, not new genes, but new genotypes. In  the
> absence  of  genetic  diversity  of  the parent stocks, it is, of
> course, impossible. In its presence, it increases the  diversity.
> A  new book can add diversity to literature, even if all its words
> are already in the dictionary. So with genes and genotypes.

Wrong.  Flat wrong.  *NO* new genotypes are created by sexual
reproduction, cross breeding or not.  New phenotypes may possibly be,
but not likely.  New genotypes are created *ONLY* by mutation.  Your
analogy to a new book created out of words in the dictionary is totally
misleading.  Who arranges the words/genes in your scenario?  Sexual
reproduction is a random selection from the parents.  A more accurate
analogy would be the random selection of half of the short stories from
each of two anthologies to form a new anthology.

> A new habitat starts new genetic trends. It is true that, left to
> nature,  they  don't  create  new  variations soon. (But they can
> create many of them in parallel).

But even in parallel we could only acheive rates far lower than those at
which species are currently being destroyed in parallel.  Plus
destroying 50% of the present diversity while creating a similar
quantity of genuinely new species and variants does *NOT* mean we
haven't lost anything.  We've still lost 33% of diversity that might
have existed without the destruction.

> We breed drug-resistant strains of germs, pesticide-resistant
> strains of pests only too fast - even without mutating them
> intentionally...

We do *NOT*.  This occurs primarily by further *DECREASING* the
diversity of an existing pest species by killing all the non-resistant
members.  A mutation in a pest species to gain resistance is very rare
indeed, and I haven't heard of an unambiguous case of it.


These and similarly mistaken points raised by Jan have convinced me that
he vastly overestimates the current state of knowlege in genetic fields,
and vastly underestimates the remaining work to be done before we can
either preserve or engineer viable living species.  The most we have
done so far is shuffle what is already present in nature.

--
Nature abhors a hero.   --- Solomon Short {quoted by David Gerrold}
-- 
Wayne Throop      <the-known-world>!mcnc!rti-sel!dg_rtp!throopw