Amazing Fish Adaptive Design  The same basic kind of fish,
called the stickleback, inhabits salt or fresh water and lakes
or streams. Strikingly, however, those living in salt water are
much larger and have different colors and different scale armor
than their freshwater counterparts with whom they can
interbreed. One generation of the marine variety can give rise
to a generation of freshwater versions, and vice versa. Are
these fish evolving, or were they created to make these kinds of
body changes within their kind?  Researchers scoured DNA from 22
representative stickleback fishes for any sequence differences
that might be linked to saltwater versus freshwater
environments. Their research should help answer questions about
how fishes adapt to their surroundings and how closely those
processes match standard ideas about evolution.  According to
the Nature study, the team gathered interesting results,
including specific sites of DNA differences that were directly
linked to the fish's environment. They found