Dog Coat Color Genetics Trivia Quiz

Answer: eumelanin and phaeomelanin

Eumelanin is black pigment that can appear as black, brown or grey. Phaeomelanin is red pigment that can appear as yellow, orange, tan, or red. White is not a pigment, but a lack of pigment.

Answer: Extension locus

The genotype at the Extension locus determines whether a dog is solid colored (either red/yellow or brown/black) or whether the Agouti locus can dictate coat color. If the dog is E or EM at the Extension locus the dog will either be black, or Agouti will cause various coat color patterns. If the dog is e/e at Extension, phaeomelanin will be produced resulting in a red/yellow coat color with no presence of black or brown.

Answer: spotted

Various Agouti alleles are responsible for sable/fawn/tipped, banded, black and tan, and recessive black coat colors.

Answer: heterozygous

Homozygous recessive (m/m) dogs are deeply pigmented. Heterozygous (M/m) dogs exhibit the merle phenotype. Momozygous dominant (M/M) dogs, also called Double Merle, are mostly white and have a higher incidence of congenital hearing and vision defects.

Answer: Shetland Sheepdog

Most herding breeds exhibit a black coat color due to the Agouti locus. When the recessive allele of Agouti is inherited homozygously, a solid black coat color is produced. The other breeds listed are black due to the dominant allele at the Extension locus in conjunction with the K gene, of which little is known at present.

Answer: a blue Doberman Pinscher

The Old English Sheepdog, Kerry Blue Terrier, and Bedlington Terrier develop their light grey or blue color with age. They are all born dark in color, either black or dark grey, and change to a lighter grey or blue after they are a few years old. A blue Doberman Pinscher is born blue and does not change color over time.

Answer: only black

Black is a dominant trait and the black Labrador Retriever is homozygous, meaning that he can only pass on the dominant black allele. The Weimaraner is homozygous for dilute, and dilute is a recessive trait, so she can only pass on the allele for dilute. Purebred Labrador Retrievers do not have the dilute allele, so the Labrador Retriever is not able to pass along dilute to any of his pups.

It is only possible for the pups to be black.

Answer: brown

The Brown locus determines whether a black dog appears as black or as brown. The dominant allele results in black pigment and homozygous recessive inheritance results in brown pigment. If the yellow Labrador is born from two brown Labradors, it can only inherit a recessive form of the Brown locus from each.

The Brown locus also affects the nose leather, so a dog that is homozygous recessive at Brown will have a brown nose.

Answer: Weimaraner fixed at dilute

All Weimaraners are fixed at dilute, that is to say, they are all d/d at the Dilution locus.

Collies can be sable, black and tan, or recessive black, in addition to various spotting patterns and merling.

Greyhounds can exhibit nearly all coat color options, including brindle.

Answer: liver

All the options listed can appear, but only black and liver (brown) are acceptable for showing. Blue actually refers to gray spots, rather than blue, but is standard terminology. Sometimes Dalmatians will have a mix of spots, e.g. black and brown on the same dog, but this also does not meet breed standards.