The C gene is especially interesting. In many animal species it is called ALBINO. Others refer to it at the CHINCHILLA gene or the CONCENTRATION gene. The C gene appears to act like a filter controlling the development and expression of the light coat pigment. The C gene is considered to mainly affect light pigment, though it may influence dark coat colour to some extent and is perhaps partially responsible for soft black, dusty darks and the like. The dominant
[ CC ] does not filter at all, and allows a deep full intensity coat to develop. Filtered red develops less colour pigment and so shows as gold, apricot, champagne, cream etc. This may be modified further by enhancement/muting genes to make innumerable variations. Order of dominance is [ C ] > [ c ch ] > [ c e ] > [ c ]. Darker and lighter shades of each may blend into each other. For instance [ C c e ] and [ c ch c ch ] can be indistinguishable.
Note - Albino in mammals is the most extreme expression of this gene, fully recessive [cc] that prevents any colour from being made at all in coat, eyes and nose, and results in an albino animal with pink nose and red eyes (like an albino rat). Albino does not seem to appear to occur in dogs normally (though is possible) and is only mentioned here for interest sake. The white found in Havanese may actually be extremely filtered [ c e c e ] off-white. He may have some very watered colour. A white Havanese has eye and nose pigment, he is not albino.
No colour filtering at all. Full deep intense colour develops.
Phenotype - dog displays deep red
Genotype - [ CC ]
Gold: One copy of the [ ch ] gene causes some degree of colour filtering. The red pigment development is not as intense resulting in a golden colour.
Phenotype - dog displays gold
Genotype - [ C c ch ]
Champagne: The champagne colour results from approximately half of the red colour development being filtered. There are many different shades possible and can be the result of more than one gene combination.
Phenotype - dog displays champagne
Genotype - [ C c e ] or [ c ch c ch ]
Cream: Significant colour filtering, leaving the coat a light creamy, almond colour.
Phenotype - dog displays cream
Genotype - [ c ch c e ]
White: Filtering as its most extreme. Almost all of the red pigment development is inhibited. The dog has so little colour in the coat as to appear white.
Phenotype - dog displays off-white / white
Genotype - [ c e c e ]