The Powderpuff Chinese Crested, the smallest of the hairless breeds, has a genetically recessive variant for coat that can be found in the same litter as a hairless puppy.
In 2008, Broad Institute of MIT and Harvard researchers revealed the genetic mutation behind the breed’s dichotomous coat. DNA samples from 20 hairless Chinese crested dogs and 20 powderpuffs in Switzerland and Finland were gathered, and a performed a genome-wide association scan was performed (this searched the dog genome for markers found in hairless dogs but not in powderpuffs).
The scan produced one strong signal, pointing to a roughly million-letter-long section of chromosome 17. To focus on the gene even more, the researchers compared this section of DNA in Chinese Cresteds to two other hairless breeds, the Mexican and Peruvian hairless dogs, that also had both a hairless and coated variety. They found that hairless dogs in the three breeds shared a 102,000-letter-long block of DNA that contains only two genes. One of them, “FOXI3,” is similar to a family of mammalian genes with roles in development, suggesting to the scientists that it might harbor the hairless mutation. Indeed, they found that “Foxi3 gene” was active in developing hair and teeth, supporting its possible role in hair and teeth abnormalities in hairless dogs.
The researchers examined the precise sequence of DNA in the 102,000-letter stretch shared by the hairless Mexican, Peruvian, and Chinese crested to identify the exact mutation. One peculiarity was found in the DNA of all 140 hairless dogs, but none of 87 coated dogs tested: Seven letters of repeated DNA in the FOXI3 gene that completely shifts how the DNA is made into protein.The three breeds originating in different parts of the world all share exactly the same seven-letter DNA change, suggesting they’re all descended from the same, ancestral hairless dog. The scientists determined that all living hairless dogs in the three breeds they studied are heterozygous for the mutation, and that having one normal version of the gene may give the hairless dogs sufficient normal protein to survive, but not enough to generate a full coat of hair.
Chinese Crested Hairless by Tobiasz Stefaniak
Maybe the Gordon Setter…how awesome would that be back-to-back with the Irish last week (which was also awesome!)
What produces the hairy hairless chinese crested?
Cynthia, the PhD after your name makes us think you might find this interesting, let us know if it answers your question: https://www.pawprintgenetics.com/products/tests/details/192/?breed=25