Cam wrote:

Some species naturally produce a lot of mutants (e.g. goldfish,
guppies, day lilies) and some have bred relatively true for millions of
years (e.g. sharks, roaches, ferns). If goldfish didn't produce the
variation that they do it would be difficult to select for desired
traits.

Oh, _that's_ why we aren't raising sharks in our ponds :-)
--
derek