Cats
There is also a brief guide to Shaw's terminology at the end
as Shaw's writing pre-dated modern "standard" symbols and terminology.
Don Shaw was an early feline geneticist in the USA. During the 1950s and 1960s, there was
no standard form of genetic coding and Shaw used his own system of genetic coding which
can be difficult to read today. He also referred to chocolate, which is a mutation of the black
gene, as "chocolate dilution". What modern fanciers call dilution, Shaw called "maltesing"
(Maltese i.e. blue cats were a genuine dilution of black). Shaw viewed dilution as being due
to the reducing amount of melanin present in the hair and not by the way pigment forms
clumps in the hair. Chocolate had less melanin than black, therefore Shaw called this dilution.
Blue has a the same amount of melanin, but arranged differently, so Shaw did not consider
this dilution.
In simple terms, the black (eumelanin) colours in cats is due to a series of genes (alleles to be
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