Tag archives: Genetic Mutation

A medium-sized retriever, the Nova Scotia duck tolling retriever is a hunting dog that is used in a most unique manner. Instead of sitting steady in the duck blind and waiting for the gunner to drop birds, the toller is an active participant in the hunt.

While the hunter remains hidden in the blind, tollers work the shoreline, darting in and out of the brush. Waterfowl, their curiosity piqued by the motion and the flashing white patches on the toller’s reddish coat, come closer to investigate. At that point, the hunter rises from his hiding spot, causing the ducks to flush. After the gunner drops the birds, the toller swims out and retrieves the waterfowl and delivers them to the hunter’s hand.

Originating, not surprisingly, in Nova Scotia, Canada, the toller was developed in the early 19^th Century. It’s the smallest of the retriever breeds and is often mistaken for the more common golden retriever. The origins are unknown, but likely consist of a red decoy dog of some sort brought to the new world by settlers and then mixed with spaniel, setter and retrievers, as well as perhaps some type of collie, according to the AKC. It was originally known ...

Since I started my work with Paw Print Genetics^TM and began discussions with many in the canine community, I have been asked more about hip dysplasia (HD) than any other disease.  Perhaps it is due to the significant decrease in quality of life it can create for affected dogs or perhaps it is because historically, it has been one of the most extensively studied canine diseases.  Regardless of the reason, it is clear to me that dog owners and breeders are concerned about the disease and would love to see it eradicated.  Unfortunately, we may be years off from fully understanding all of the contributing causes and thus, preventing this often debilitating disease.

In the most basic sense, HD is simply a condition of loose hip joints, but it is the secondary consequences of these loose joints that cause the clinical condition we recognize in dogs.  In affected dogs, laxity in the hip joint leads to abnormal alignment between the head of the femur and the pelvic socket (acetabulum) that serves as the gliding surface for the head of the femur during movement.  This improper alignment leads to abnormal wear and tear of the ...

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 ...