GENETIC TESTING FOR COAT COLOR AND LENGTH IN THE SHIBA INU
(photos from NSCA website at shibas.org)
There is another gene in the agouti series for recessive black labeled “ a ” which is recessive to black & tan. This is not the dominant black seen in most breeds like the Labrador or Chow, but is the black of the uncommon black German Shepherd, black & white Sheltie, or the very rare black Samoyed or American Eskimo. The Shiba does not appear to carry the reces- sive a . The lab will test for the A series and look for the three things that are known, Ay sable, at black & tan, and a recessive black. If the dog only has one of these, then it is assumed that the other is aw , the wild color. Very few Shibas have been test- ed that are suspected of carrying the aw gene, but those that have been tested are aw/at sesames. By appearance, the aw/at sesames have a wider distribution of dark hair than the ay/at sesame, the dark hair extending down the bridge of the nose without a widow’s peak. It is also possible for a Shiba to be aw/aw , but no dog that has been tested has had that color. It is possible for a Shiba to appear to be sesame but actually not carry the at gene, as Ay/ Ay , the gene for sable, allows for black hairs. Of course, if a dog has a black & tan parent, it will carry the at recessive. Four cheek swabs were submitted to VetGen for testing, with the following results: • Dog A was a red with no known black & tan in his pedigree and never known to have produced one, and his test results came back EE , Ay/Ay , and negative for a . • Dog B was a sesame and his test results showed him to be EE , with only one copy of Ay , and negative for a , so he was Ay/at by process of elimination. At the time of submis- sion, there was no test for aw , and at was done by a process of elimina- tion. Since then, the test for at has become definitive. • Dog C was a red known to have produced cream, and his test results were Ee , Ay/Ay , and negative for a . • Dog D was a cream and her test results were ee , Ay/at , and negative for a . Although this is a small sampling, the genetics bear out what is seen in the Shiba breed. These basic coat colors and modify- ing factors that cannot be identified genet- ically at this time influence the expression of the genes. Nowhere is this more appar- ent than in the urajiro on the Shiba.
234 | SHOWSIGHT MAGAZINE, MAY 2022
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