Erwin Moller wrote:
 > Dear reader,
 >
 > I apologize beforehand if I use poor terminology: I am a programmer
 > in the first place, with a great affinity for evolution. I also
 > apologize for posting a long introduction before I arrive at my
 > question. Maybe if I knew the right words for the simulation I wrote,
 > I could do it 10 times shorter.  :-)
 >
 >

 >
 > At last I arrive at my question: (and I hope I entertained you so
 > far)
 >
 > Almost every time when I had a 'stable' situation (meaning that sheep
 > and wolfs survived without extinction for many generations) I noticed
 > that the AVERAGE mutationrate over all my animals was low. Also the
 > mutationrate had a tendicy to get lower all the time in a 'stable
 > situation'.
 >
This makes sense: the principle is that an optimum is reached, so any
changes will be moves away from the optimum.

 > Introducing a big change: When I introduced big change (like changing
 > the distance for a sheep to get the food, or change the pattern in
 > which the food was created in the playingfield) the avarage
 > mutationrate started to grow dramatically!
 >
This also makes sense.  Now the optimum has moved, so individuals which
can produce offspring that are different (i.e. some of which will be
nearer the optimum) will have a selective advantage.

 > This suprised me because I expected the mutationrate to always drop.
 > Why did I expect that? Probably because I misread 'the selfish gene'
 > of Richard Dawkins. I expected my 'genes' (neural network) to be very
 > selfish, and that it tries to copy itself as good as possible. But
 > then i struck me that it can be in the advantage of an animal to
 > introduce many mutation when the world around it changes, creating
 > possibly better offspring. I wondered: Maybe a gene that codes for
 > 'reliability of copying' exists?
 >
Not formally, but the proteins involved in DNA replication do have error
correction mechanisms, and these can presumably work with different
levels of efficiency, which would produce the variation in reliability.

 > I guess my question can be rephrased to: Is it in the animals
 > advantage to copy its genes LESS RELIABLE during environmental
 > stress?
 >
 > Does anybody know of a parrallel to the real world where this
 > happens? For example: Is there a species that can adjust it's own
 > reliability for copying genetic material actively, depending on the
 > environmental changes?
 >
There is evidence in bacteria, hopefully someone else will know the
references.  Higher organisms tend not to respond genetically, but
physiologically or behaviourally.  Evolving evolvability is a long term
business, so even if it does happen in higher organisms, I guess it 
would be difficult to find evidence for.

Bob

-- 
Bob O'Hara

Dept. of Mathematics and Statistics
P.O. Box 68 (Gustaf H„llstr”min katu 2b)
FIN-00014 University of Helsinki
Finland

Telephone: +358-9-191 51479
Mobile: +358 50 599 0540
Fax:  +358-9-191 51400
WWW:  http://www.RNI.Helsinki.FI/~boh/
Journal of Negative Results - EEB: http://www.jnr-eeb.org
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