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A-AY Locus (A-AY-LOCUS)

A-AY Locus (A-AY-LOCUS)

Agouti, Sable, Fawn

The A Locus (agouti series) interacts closely with the E, K, and B Loci which can lead to a dog’s overall coat color and pattern. A Locus mutations are only expressed if the dog is “Clear” or “Carrier” at the E locus and “Clear” at the K-KB locus. There are three potential mutations at the A Locus that can each have a different effect on coat color. The mutations are known as A-AY, A-AT, and A-A and can determine whether a dog is a Carrier of sable/fawn, black and tan/tricolor/tan points coloration, or a recessive form of a solid black or bicolor coat color. The A-AY gene mutation produces a coat color that can range from a light fawn to darker red to a sable based on variation in gene expression. Dogs that are “Clear” at the K-KB Locus and have one or two copies of the A-AY mutation will always express a sable/fawn coat color. This means a dog that appears fawn or sable can carry any of the other A-locus alleles (A-AT, A-A, or A-AW) and would not express them. The A-Locus alleles are expressed in a hierarchical manner with A-AY being dominant to and expressed over A-AW, A-AT, and A-A. It is important to note that the dog’s coat color is also dependent on the dog’s genotype at E, K, and B Locus among others.

Reading Your Results

A. (CLEAR/NORMAL):

These dogs have two copies of the normal gene and the effect of A Locus on their coat color can be determined by testing at the A-AT and A-A loci. They will also not pass this mutation to any of their offspring.

B. (CARRIER/AFFECTED):

These dogs have one copy of the normal gene and one copy of the mutation associated with sable/fawn coat color. They will exhibit a sable/fawn coat color and the effects of A Locus on offspring coat color can be determined by testing at the A-AT and A-A loci. They will, if bred, pass the mutation to 50% of their offspring, on average.

C. (AT RISK/AFFECTED):

These dogs have two copies of the mutation and will develop a sable/fawn coat color due to the A-AY mutation and will pass this mutation to 100% of their offspring. However, this dog’s coat color is also dependent on the E, K, and B Locus genes.

Additional Details

Inheritances

Complex Order Of Dominance With Other A Locus Mutations (AY > AW > AT > A) And Also Depends On Results For E, K, And B Locus Mutations

Affected gene

ASIP

Chromosome

Ch. 24

Mutation

C.244G>T and 248G>A

Publication:

Berryere, T.G., Kerns, J.A., Barsh, G.S. et al. Association of an Agouti allele with fawn or sable coat color in domestic dogs. Mamm Genome 16, 262–272 (2005). [PubMed: 15965787]