In order to attain a puppy with a blue coat and it's associated blue nose, each parent must be carriers of the recessive dilution gene. (dailydogdiscoveries.com)
They also possess a strong color dilution gene which means the coat color fades to white or champagne as a Coton matures. (americancotonclub.com)
A horse can carry more than one dilution gene which can further affect coat color. (animalgenetics.us)