Chocolate in Chihuahuas, no, it’s not diluted!

Oh my, so many times I hear that chocolate (brown, liver) is diluted, and no, it is not. Chocolate or liver is bb in the genetic code. It refers to the pigment of the eye rims, nose, and paw pads; therefore, we can have chocolate fawns, Chocolates with tan points, and many other combos. You may sometimes hear liver or liver dogs being described as "dilutes." The liver is not technically dilution but just a different color of eumelanin. Dilution in dogs is controlled by a separate locus and causes blue and Isabella/lilac.

A & A's Top Pocket Find " Gary"

"Gary" A Chocolate Long Coated Chihuahua with white markings

The liver gene occurs on the B locus and causes a brownish color. It's recessive, so b is liver, and B is non-liver, and for a dog to be liver, it must have the genotype bb. This means that a liver puppy can be born from black parents if both are carriers of the liver allele (i.e., if both are Bb, then at least one pup in four will be bb)

The different pigment color genotypes are: BBdd or Bbdd - blue (non-liver, dilute) BBDd or BBDD - black (non-liver, non-dilute) bbdd - isabella (liver, dilute) bbDd or bbDD - liver (liver, non-dilute)

The liver gene affects eumelanin (black pigment) only. All the black in the coat will be turned to the liver (brown) when a dog is bb on the B locus. This includes saddles, shading, merle, etc. It is genetically impossible for a liver dog to have even one black or grey hair or a black or blue dog to have liver in its coat (although bronzing and sealing may look slightly like a liver). However, a liver dog may have some "red" (phaeomelanin) hairs depending on the K and A locus alleles present.