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Clear, Carrier & Affected



Breeding advice for most DNA tests (autosomal recessive conditions)

An autosomal-recessive condition means that a dog must inherit two copies of an abnormal gene (one from its mother and one from its father) before its health is affected. 

How are results recorded?

Tested dogs will be recorded on our systems as “clear”, “carrier” or “affected”.

  • Clear - these dogs do not have any copies of the abnormal gene associated with the condition that has been tested for. These dogs are highly unlikely to develop this condition and will pass on a normal copy of the gene to their puppies

  • Carrier - these dogs have one copy of the normal gene and one copy of the abnormal gene associated with the condition that has been tested for. These dogs are highly unlikely to develop this condition and may pass either one copy of the normal gene, or one copy of the abnormal gene on to their puppies

  • Affected - these dogs have two copies of the abnormal gene associated with the condition that has been tested for. These dogs will likely be affected by the disorder and will pass on one copy of the abnormal gene on to any future puppies

Breeding advice for autosomal-recessive conditions

The table below provides guidance on breeding from your DNA-tested dog.


If your dog is clear

Clear dogs can be mated to any dogs without producing affected puppies. If they are bred with a carrier or affected dog they may produce carrier puppies.

If your dog is a carrier

Carrier dogs can be used for mating, so long as they are only mated to clear dogs. Mating a carrier to a carrier, or a carrier to an affected dog is putting the health of future puppies at risk.

If your dog is affected

Affected dogs can only be mated to clear dogs without risking producing affected puppies, however all resulting puppies will be carriers. Mating an affected dog to a carrier, or another affected dog is putting the health of future puppies at risk.

Potentially producing affected puppies

Producing affected puppies that will develop the condition you tested for will have a serious impact on their health and welfare. A mating that may produce affected puppies should never knowingly be carried out. If this mating accidentally occurs, it is important to test all of the puppies before they are bred from or are passed on to new homes. Veterinary advice should be sought as to the clinical management of any affected puppies.

Why breed from carriers and affected dogs?

Breeding only from clear dogs can have a significant impact on genetic diversity within a breed, increasing inbreeding and therefore the likelihood of new inherited diseases emerging.

  • With simple autosomal-recessive disorders, a carrier will not be affected by the condition you have tested for, but they could pass on a copy of the faulty gene if they themselves are bred from

  • Only when a dog inherits two copies of a faulty gene (one from its mother and one from its father) will it be affected

  • When used responsibly, carriers are an important part of any breeding plan and should not be overlooked

  • By breeding from carriers, you can keep good, healthy dogs in the breeding population, helping to maintain genetic diversity

  • Ultimately, however, over the course of a few generations it would be beneficial to aim to produce only clear puppies, thereby reducing the frequency of the disease-causing variant of the gene in the breed

Similarly an affected dog could still be used in a breeding programme, but this will very much be dependent on the condition and whether the dog's welfare would be affected by the mating/whelping process. They should only be mated to clear dogs, to ensure no affected puppies are produced.

Are clear dogs 100% clear?Additional cautions about using carriers or affected dogs

Making balanced breeding decisions

As well as considering the implications of a dog’s DNA test results, there are other equally important factors to consider when deciding whether two dogs should be mated together, such as temperament, genetic diversity, conformation, other available health test results, the general health of the dogs etc. Your breeding decisions should always be well balanced and take into consideration the qualities and compatibility of both the sire and dam that you are considering.





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