Before Jimmy Fallon, Jay Leno and David Letterman, there was Johnny Carson, and one of his best known and recurring comedic “shticks” was “Carnac the Magnificent,” a “mystic from the East” who could “divine” the answers to questions on paper that he had never seen before.
You, too, can wow your friends by divining the genetics of a Chinese Crested Hairless simply by looking in the dog’s mouth. Oooooh, aahhhhhhh.
To determine whether a Chinese Crested is genetically Hairless or a Powderpuff, simply look in its mouth.
It isn’t magic, however, it’s science.
For 500 years, the idea that there was a genetic link between the hairless trait and incomplete dentition was considered malarky even though anecdotal evidence showed otherwise. We know today that if the dog is genetically Hairless, it will have forward pointing “tusks.” If the dog is a Powderpuff, it will have a normal mouth. The gene that causes hairlessness in the Chinese Crested is dominant to the gene of the coated Powderpuff, and the gene responsible for this hairless trait triggers development of hair and teeth. Many (but not all) hairless dogs have missing or abnormally shaped teeth, but coated dogs in this hairless breed (the one-fourth of hairless dogs that are born with hair) have strong, healthy teeth because the Powderpuff carries no Hairless genes, and therefore, their mouths aren’t impacted by the Hairless gene mutation.
Missing hair and teeth is a phenotype termed “canine ectodermal dysplasia,” an inherited monogenic autosomal semi-dominant trait. Often (but not always), the canines in some Chinese Crested mouths are conical shaped, and if they’re large, they’ll push the teeth forward. Again, these teeth are referred to as the aforementioned “tusks.”
The shape of the incisors can vary quite a bit as well. Some of the front teeth in hairless Cresteds are smaller, and more like “chiclets” – little pegs protruding from the gums. Others are almost normal. Sometimes a full complement of narrow “pegs” can look as though they have been thrown in haphazardly. The number of teeth present can also vary. In the worst example, many may be missing, having never been present at all.
Most are of the opinion that in judging both varieties, emphasis should be put on expression, sound structure, balance and movement. Since the Powderpuff variety doesn’t carry the hairless gene, a full and normal dentition is expected, while a Hairless shouldn’t be penalized for lack of dentition.