E Locus - E^h (Sable, Cocker Spaniel Type)

Testing Summary

The E^h Locus (Sable, Cocker Spaniel Type) coat color test evaluates the MC1R gene to determine the E^h locus genotype for the dog. This Mutation has been associated with the ‘sable’ appearance in Cocker Spaniels. This specific sable coat color is not caused by the A locus as seen in most breeds including the Cocker Spaniel, but is a variant of the E locus. This sable coat color/pattern shows a darker brown or black pigment on the head and neck of the dog which lightens to a cream/tan pigment down the body of the dog and muzzle. This mutation is recessive to the E Allele (which allows dark pigment) and dominant to the e allele (red/apricot/cream) that is tested through the E locus test (E>E^h>e).

Dogs with E^h/E^h or E^h/e genotypes typically have a pattern of dark pigment on their head and lighter pigment on their body. However, there are other genes that influence the final coat color and pattern of the dog. For example, a dog must have at least one copy of K^B at the K locus (K^B/K^B or K^B/k^y) to express this sable pattern and dogs that inherit two copies of k^y (k^y/k^y) will instead display lighter red hair with darker tips. Dogs that carry at least one copy of E^h can produce sable dogs if bred to another dog that carries at least one copy of sable (E^h/E^h, E/E^h or E^h/e) or carries at least one copy of red/cream (E/e or e/e).

The E^h Locus (Sable, Cocker Spaniel Type) coat color test reliably determines if a dog has one of the following genotypes at the E^h locus:

Detailed Summary

The E^h Locus (Sable, Cocker Spaniel Type) corresponds to the MC1R gene that is important in determining the production and pattern of pigment. Mutations in this gene can alter the expression of the dark pigment called eumelanin or can eliminate the expression of eumelanin in the coat altogether. These mutations include E^m, E^g, E^h, and e. Canine coat color determination is complex due to interactions of multiple genes responsible for both color and anatomic placement of the color. A dog with two E^h copies of the MC1R gene will have a ‘sable’ pattern which is different than the sable caused by the A Locus. A dog with only one copy of the E^h Mutation may show the sable pattern if they also carry an ‘e’ at the E Locus. The K locus can also alter presentation of the sable. One or two copies of ‘K^B’ at the K Locus will give a sable pattern. A dog with two copies of ‘k^y’ at the K Locus will have a lighter red sable pattern with fewer dark hairs.

Testing Tips

Genetic testing of the MC1R gene will reliably determine the number of copies of the sable (Cocker Spaniel type) gene Mutation that a dog carries. Eumelanin patterns are associated with mutations of the MC1R gene and are inherited in a complex manner in dogs and show a specific pattern of dominance with E^m>E^g>E>E^h>e. Dogs that carry one copy of E^h (E^h/N) with E/E at the E Locus do not display a sable pattern. A Carrier dog (E^h/N) with an ‘e’ (E/e at the E locus) will show the sable pattern. Dogs with two copies of ‘e’ are cream or red and cannot show the sable pattern even if they have one or two copies of E^h. Reliable genetic testing is important for determining breeding practices.

There may be other causes of this condition in dogs and a normal result does not exclude a different mutation in this gene or any other gene that may result in a similar genetic disease or trait.

References