GENETICS IN A NUTSHELL

Genetic testing is vital to a conscientious reputable breeder's program. By breeding only an animal that is genetically clear (n/n) to a mate that is either only a carrier (mutant/n) or is also genetically clear (n/n), the breed remains strong and the recessive (or bad genes) that cause the most common diseases and disorders are maintained at the most minimal level. This should be the responsibility of every breeder- to preserve the breed and/or even make it stronger. These tests are fairly new and do change occasionally, depending on current ongoing research. For them to be effective, they should be done on every animal in the breeding program. This can get very costly, as you could imagine, so this is one of the many reasons that a puppy from a reputable breeder costs more. In this case, you could very well “get what you pay for” if you settle for a cheaply priced puppy. Once the parents are tested, you can predict within a certain probability what the puppies will carry genetically in their profile. Each parent has two copies, or alleles, of gene trait and only gives one copy to each individual offspring. So the results of a test can be: normal/normal (n/n) – meaning that gene isn’t in the animal at all and never will be expressed, Mutant/normal (m/n) – meaning they are a carrier for that gene but in most cases will never express that gene, or Mutant/Mutant (m/m) – meaning they have both copies of that gene, will pass it on to offspring, and will express, or be affected, by that trait. If both parents are n/n for a trait, then the puppies will also be n/n for that trait and not carry it at all, because the parent didn’t have the trait to pass on. If either parent possesses even one copy of a trait, the chances of any puppy in a litter being a carrier for that trait is 50/50 as the parent has a 50/50 chance at giving that particular puppy one copy of the gene. If there is even a 50/50 chance of a puppy being a carrier of a trait and the puppy will possibly be bred at any point in its life, that puppy should be tested before being bred to see if it is a carrier or not.

 

I will use MDR1, or the drug sensitivity gene, as an example, but this applies to all genes. This is the gene that says whether or not your dog will be susceptible to seizures and/or other adverse reactions if given certain medications, like the wormer Ivermectin.

 

Example 1

Sire (n/n) Dam (n/n)

All Puppies (n/n) – will not express or carry this trait

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Example 2

Sire (MDR1/n) Dam (n/n)

Puppies (MDR1/n) – will carry but most likely not express the trait

or (n/n) – will not express or carry this trait

 

* I DO NOT PROMOTE OR PRACTICE THE BREEDING OF ANY ANIMAL THAT FALLS BELOW THIS LEVEL *

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Example 3

Sire (MDR1/n) Dam (MDR1/n)

Puppies (MDR1/MDR1) – will be sensitive to drugs

or (MDR1/n) – will carry but most likely not express the trait

or (n/n) – will not express or carry this trait

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Example 4

Sire (MDR1/MDR1) Dam (MDR1/n)

Puppies (MDR1/n) – will carry but most likely not express the trait

or (MDR1/MDR1) – will definitely express the trait

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Example 5

Sire (MDR1/MDR1) Dam (MDR1/MDR1)

All Puppies (MDR1/MDR1) – all puppies will have the drug resistance problem

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La Dolce Vita Farms Genetic Testing

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I use Animal Genetics Laboratory for my testing unless there is something specific I am concerned about or interested in that they do not offer. They offer a panel of the most common genetic defects specific to the Australian Shepherd which includes at this time:

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• CEA – Collie Eye Anomaly is a bilateral eye disease. It causes abnormal development in layers of the tissue in the eye under the retina called the choroid. In most cases, this is present at birth and can be detected as young as 4-8 weeks of age.

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• HC – Hereditary Cataracts (HSF4) are a clouding of the lens of the eye caused by a breakdown of tissue. It in general results in the dogs inability over time to see clearly and/or may cause total blindness. The age of the onset and/or rate of progression of the cataracts is not predictable. The cataracts can be corrected with surgery and treatment, although it is a very costly process.

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• MDR1 – Multi-Drug Resistance is a condition related to a gene that codes for a protein responsible for transporting potentially harmful chemicals away from the brain. If this gene isn’t working correctly then harmful drugs, Ivermectin, Loperamide and a number of other drugs are not removed from the brain causing a buildup of toxins. This buildup can cause neurological symptoms such as seizures, ataxia (wobbly movements) or even death.

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• CMR1 – Canine Multifocal Retinopathy causes raised lesions to form on the retina changing the appearance of the eye but usually not affecting sight. These lesions can appear at only a few months old and may disappear or may cause minor retinal folding.

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• CD – Cone Degeneration is a disease that causes day-blindness caused by a lack of cone function in the retina of the eye. This can develop between eight and twelve weeks of age. Vision is only affected in bright light. The dog’s vision is not affected in dim light.

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• DM – Degenerative Myelopathy is a progressive neurological disorder that affects the spinal cord. There is a breakdown of the cells responsible for communicating signals to and from the brain resulting in neurological symptoms such as an unsteady gait, wobbly walk. As this progresses, the hind legs will become so affected that the dog is no longer able to be mobile, the bladder will lose control and eventually it will move up to the front legs as well. This is not a painful disease for the animal but it is limiting and hard to manage.