Tag archives: dysplasia

The Genetics of Hairlessness

The Genetics of Hairlessness
A hairless Chinese Crested next to a Powder puff

Aficionados of the hairless breeds are motivated to perpetuate and conserve these very historical and special dogs. The Xoloitzcuintles (“show-low-itz-QUEENT-ly.” or just Xolo “SHOW-low”) and the Chinese Crested dog are the more common hairless dogs but are no means the only hairless breeds. Some controversy surrounds the hairless breeds due to the nature of the hairless gene variant and its inheritance from one generation to the next. Looking at some basic genetics and how they apply to the inheritance of the mutation responsible for hairlessness will benefit the breeder trying to determine the best pairing for these unique dogs.


All genes are inherited from the parents. Half of the genetic material, or alleles, come from the mother, the other set of alleles come from the father. Two alleles, one from the dam and one from the sire, make up the genotype. The genotype will then determine the phenotype, or what trait or condition we observe in the dog. Further, we define genes as either being dominant or recessive. A dominant gene requires only one allele, passed from one parent, to express its phenotype. Whereas, a recessive gene requires two alleles, one passed from each parent, for its phenotype to ...

Picking the Right Genetic Test for Canine Progressive Retinal Atrophy

Picking the Right Genetic Test for Canine Progressive Retinal Atrophy

Canine progressive retinal atrophy (PRA) is a group of inherited eye diseases which are among the most common causes of inherited blindness in domestic dogs. Extensive study and characterization of the various PRAs have led to the discovery of well over a dozen different genetic mutations in many different genes which can now be identified to help prevent, predict, or diagnose PRA in many breeds. However, complicated PRA naming schemes and the breed-specific nature of the PRA tests can make it challenging for dog breeders or veterinarians to select the correct test for the dog in front of them.  

Multiple Genes, Similar Clinical Findings

The known underlying mutations associated with the various forms of PRA are found in a wide variety of different genes. Thus, highlighting the complexity of the biological pathways involved in the development and ongoing maintenance of the eyes. PRAs are marked by the abnormal development and/or the gradual degeneration of rod and cone photoreceptor cells of the retina. Each type of PRA may display variation in the age of onset, speed of disease progression, and the relative rates at which each of the two photoreceptor types are destroyed. However, when it comes to clinical ...