UC Davis School of Veterinary Medicine Veterinary Genetics Laboratory

Hairlessness in Terriers


Hairlessness in the dog has evolved independently at least twice. One form of hairlessness present in several breeds (Peruvian Inca Orchid, Chinese Crested, Mexican Xoloitzcuintle) is inherited as a dominant trait and is lethal in the homozygous state (two copies of the mutation). A second, recessive form defines the American Hairless Terrier, a breed thought to be derived through selective breeding from the Rat Terrier. Contrary to the dominant form, there are no adverse effects on dentition or fecundity associated with the recessive Terrier hairlessness.

Although the trait breeds true in the American Hairless Terrier, outcrosses are performed to systematically introduce variation and create a healthier, more diverse gene pool. These crosses benefit from DNA test results, which will assist breeders in identifying the coated dogs that carry the hairless mutation.

A DNA test for the recessive Terrier hairless trait is now available through the Veterinary Genetics Laboratory. This test distinguishes dogs with respect to the mutation: coated and clear (no mutant copy), coated and carrier (one mutant copy), or hairless (two mutant copies).

Allow 3-6 business days for results.

Test Results reported as:

C/C: Coated - The dog does not have the hairless gene.

C/H: Coated and Carrier - The dog has one copy of the hairless gene.

H/H: Hairless - The dog has two copies of the hairless gene.

If a carrier dog (with a single copy of the hairless gene) is used in a mating, an offspring from the cross has a 50% chance of inheriting the mutation from this parent. If two carriers are mated, 25% of the offspring in the litter are expected to be hairless and another 50% of the puppies are expected to be carriers of hairlessness. Mating two clear dogs (C/C) will only produce clear puppies, which need not be tested by DNA.

Submitting a sample for DNA testing is simple. Cheek swabs can be non-invasively collected from a dog in just a few minutes. Samples can be submitted by regular mail.

Please note: This test is specific for the recessive mutation present in the American Hairless Terrier. It does not detect the dominant mutation found in the Peruvian Inca Orchid, the Chinese Crested, and the Xoloitzcuintle breeds.

Veterinary Genetics Laboratory, Tel 530-752-2211, Email VGL