Tag archives: dog mutation

Another non-intuitive but common behavior of genes is that one gene can have different but apparently unrelated effects. This is somewhat the opposite of different genes having the same effect (discussed in my previous blog). Making it even more confusing, the same condition could have both at work!

One gene may create a specific appearance but can also cause issues that would not necessarily appear to be related. In scientific terms the word pleiotropy is used to refer to the phenomenon "when one allele or pair of alleles has different effects - particularly when these effects appear unrelated."

Many examples of this phenomenon exist in the dog world. With on-going research, more will no-doubt be identified.

The gene causing Merle color pattern increases the chance for deafness and eye defects. Certain "white" dogs also have increased risk of deafness related to being white. In other breeds, very white appearing dogs (due to other genes) and dogs with albinism have no associated risk for hearing loss. In the case of the Merle and "white piebald" associations the effect begins on cells derived from the neural crest affecting both pigment, auditory and potentially other neural-derived cells, but not all Merles, double merles and ...

Labrador Retrievers are the most popular breed in the U.S. and in addition to making great pets, are commonly used as working dogs for hunting, seeing-eye dogs, and therapy dogs. Labradors carry a particularly large burden of genetic diseases, including diseases that can affect young pups. One such disease is Pyruvate Kinase Deficiency of the red blood cells (PKD). Symptoms may present as early as 2 to 3 months of age, presenting after the puppy has been purchased and delivered to their new owners.

Affected dogs have a hemolytic anemic that results in fewer red blood cells. The affected dogs tend to be smaller and weaker than their littermates. Other symptoms include exercise intolerance, pale mucous membranes, fast heart rate and heart murmurs. Enlargement of the spleen and liver is usually present by a year of age, and bone marrow and liver failure may occur by 5 years of age. Bone marrow transplant has been successful in treating the symptoms in affected dogs, although the cost prohibits this treatment in most affected dogs.

Genetic testing of the PKLR gene in Labrador Retrievers is available. Because this disease is inherited in a recessive manner, the mating pair may be carriers ...