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From: marcoj@ai.rl.af.mil (James D. Marco)
Subject: Re: recessive & dominance
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Date: Mon, 19 Jun 1995 14:35:16 GMT
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In article <3rss69$pp0@sct1.sct.fr>, sekine@world-net.sct.fr (sekine) wrote:
> Could anyone explain what is it?

**Your answer**
   Basically a simple thing.  Given an environment where two genes
-D(dominant) and R(recessive) - are capable of controlling some single
characteristic C, all attributes of C will be defined by D-dominant;
R-recessive is unused.  Hence, D is said to completely mask R. This is the
simplest occurrence of a genetic dominant/recessive pair.
**A little more**
   Partial dominance is more complex, since both genes contribute to
defining attributes for the characteristic.  Both are evaluated.  In
natural biology, it is sometimes the case where a third gene -T- will
control the process of selecting which attribute, from which gene is used.
The activities of T are often controlled by the presence or absence of 
one or more environmental influences and/or other genes.  A high degree of
complexity is a given (every molecule, hence every atom of a natural gene
conveys information - even if the information is NOP - no process, a place
holder ).
   Most genetic algorithms and genetically based programs do not model the
natural biology of a living organism.  Genetic pairs in particular are not
usually modeled, soooo..., no recessive or dominant nor partially dominant
genes and their related control structures are found.
   Genetic algorithms are in their infancy.  Selection mechanisms - for
producing the correct set of attributes from an attribute pool to produce
a single desirable characteristic - seems to be the focus of most GAs.
   Allowing me a high degree of simplification,  let me define some levels
within a genetically based organism for you:
      (No flames please, this is an over-simplification in most regards!)
      1) a gene is a template for the production of  a protein. 
      2) a protein is a structural component of a cell.
      3) a cell is a component of a tissue
      4) a tissue is a component of an organ
      5) an organ is a component of an (organ) system
      6) a system is a component of an organism 
      7) an organism is a component of a society . . .
      8)  . . .  
   Most GAs fall into the level 1 category.  Production of a single
response to a single set of conditions within a single environment. For
example: solving the correct path in a maze.

   Probably a little more than you wanted, hope it was enough.
                 @;-)                           marcoj@ai.rl.af.mil
