Xref: utzoo sci.bio:2018 talk.origins:4977
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From: gary@percival.UUCP (Gary Wells)
Newsgroups: sci.bio,talk.origins
Subject: Albino Fish (was Re: The birds and the beaks)
Message-ID: <1490@percival.UUCP>
Date: 21 Apr 89 23:46:36 GMT
References: <273@acates.UUCP> <1947@ditsyda.oz>
Reply-To: gary@percival.UUCP (Gary Wells)
Followup-To: sci.bio
Organization: Percy's UNIX, Portland, OR.
Lines: 28




>in article <273@acates.UUCP>, dan@acates.UUCP (Dan Ford) says:
>> 
>> It seems to me that not all evolution can be explained in terms of simple 
>> environmental selection.  My example is the albino cave fish, shrimp, and
>> various varied darkness dwellers.  These critters ware decendants from colored
>> animals, and yet that have become albino.  This cannot be due to environmental
>> selection, since you cannot have selection for (lack of) color in the black
>> caves.  It is a repeatedly seen pattern of change, and not a single odd
>> species mutation.

It could also be that the coloring agents in the skin need exposure to UV (or
some other component) to "darken".  I think that myolin is the pigment agent
in human skin, and that is definitely sensitive to UV (thus sun tans).  I may be
wrong on the name of that pigmenting agent, but the fact remains.

Has anyone tried exposing any of the cave-albinos to normal levels of UV and
checking what happens to the skin color?

Just thinking out loud, here.

-- 
--------------------------------------------------------------------------------
Still working on _natural_ intelligence.

gary@percival   (...!tektronix!percival!gary)