Understanding and using your dog’s DNA test results

Beagle having its mouth swabbed
DNA tests are a great way for you to understand your dog's genes and can help people who are thinking of breeding from their dog to avoid passing on inherited conditions to any future puppies, or can help owners to know what conditions their dog may develop as they get older. Once your dog has been tested, understanding what your results might mean or how to use them responsibly can be difficult, so we've created the guide below to help you.

Get the right advice for your DNA tests

The breeding advice for most of the DNA tests that we record is the same because many of these conditions are inherited in the same way (known as autosomal-recessive conditions). But, we do also record a small number of other types of DNA test.

The breeding advice below applies to many of the conditions that we record, but before using our breeding advice it's worth checking that the DNA tests that you've used on your dog are not one of these other types of test. The breeding advice for these other tests may be slight different and you should go to the relevant section below.
Other DNA test types

Most of the DNA tests that we record are for autosomal recessive conditions, however the following DNA tests are for conditions where the breeding advice may be different.

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?
Clear dogs are only known to be clear for the condition that they have been tested for, and may carry other unknown mutations which can be passed on to their offspring - it is almost certain that all individuals carry some versions of genes that if inherited in duplicate would result in disease. If a particular dog has many offspring that go on to breed themselves, these unknown mutations may then increase in frequency in the breed and a new inherited disease could emerge. In other words, no dog is completely risk free, but there are ways a breeder can reduce the risk of known and unknown inherited disease. 
Additional cautions about using carriers or affected dogs

Sticking to these rules will mean that you can still use these dogs for breeding, while maintaining genetic diversity within the breed.

  • Never overuse a carrier or affected dog for mating. If a dog has one or two copies of a known faulty gene it should never be overused for breeding. Overusing these dog’s risks increasing the frequency of the faulty gene within the population, making it more difficult for future generations to breed without increasing the risk of producing affected dogs
  • Do your research. If all breeders decided to use carriers or affected dogs for mating, then there is a possibility that as the frequency of mutant genes increases, then the proportion of 'clear' dogs would decline. You can use carriers and affected, but you always want to make sure you have a big enough supply of clear dogs. You may wish to talk to health representatives at your local breed club who will have access to summary information on the results of dogs that have been DNA tested and can advise you appropriately on the current situation in your breed
  • Any possible carrier puppies that go on to be bred from should be DNA tested prior to mating. If you do decide to produce puppies that are potentially carriers, but are concerned that they may be used by their new owners for breeding, then you may wish to consider placing an endorsement on the puppy, or include a statement in your puppy contract that any puppies used for breeding must be tested prior to mating and if the puppy is a carrier, it must only be mated to a clear dog

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.

Autosomal-dominant conditions

An autosomal-dominant condition means that a dog need only inherit one copy of an abnormal gene (either from its mother or its father) before its health is affected.
How are results recorded?
Tested dogs will be recorded on The Kennel Club's systems as “clear”, “heterozygous affected” or “homozygous 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
  • Heterozygous affected - 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 will likely be affected by the disorder and could pass on a copy of the abnormal gene on to any future puppies
  • Homozygous affected - these dogs 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-dominant conditions

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

If your dog is clear

Clear dogs can be mated to any other clear dog without producing affected puppies. If they are mated to an heterozygous or homozygous affected dog they can produce puppies that are affected too.
  • Mating to a clear dog: all puppies will be clear
  • Mating to a heterozygous-affected dog: each puppy has a 50% chance of being clear and a 50% of being heterozygous affected
  • Mating to a homozygous-affected dog: all puppies will be heterozygous affected

If your dog is heterozygous affected

Breeding from this dog could produce affected puppies and is potentially putting their health at risk.
  • Mating to a clear dog: each puppy has a 50% chance of being clear and a 50% of being heterozygous affected
  • Mating to a heterozygous-affected dog: each puppy has a 25% of being clear a 25% chance of being homozygous affected and a 50% chance of being heterozygous affected
  • Mating to a homozygous-affected dog: each puppy has a 50% chance of being homozygous affected and a 50% chance of being heterozygous affected

If your dog is homozygous affected

Breeding from this dog has a high risk of producing affected puppies and is potentially putting their health at risk.
  • Mating to a clear dog: all puppies will be heterozygous affected
  • Mating to a heterozygous-affected dog: each puppy has a 50% chance of being homozygous affected and a 50% chance of being heterozygous affected
  • Mating to a homozygous-affected dog: all puppies will be homozygous affected 
Potentially producing affected puppies
Potentially producing affected puppies that may develop the condition you have tested will have a serious impact on canine health and welfare. Matings which could 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.

Linkage tests (DNA based)

Most DNA tests look for a particular gene that is known to cause a particular condition. Sometimes scientists are unable to find the exact gene, but are able to know approximately where in a dog’s genome it is located. Genes and other genetic markers are often inherited together because they are near one another on the same chromosome. While it may be difficult to identify the exact gene causing a condition, scientists are sometimes able to find sections of DNA that are usually linked to, and inherited alongside, the unknown gene. By identifying these linked genetic markers, breeders are able to know, with considerable confidence, the genetic status of their dogs.

These DNA tests may not be quite as accurate as tests where the gene is known – they rely on the link between the marker and the disease causing gene being maintained - but can still be highly accurate and laboratories will often estimate how accurate their test is.

Why do laboratories create linkage tests rather than regular DNA tests?

Laboratories may offer linkage tests for three main reasons:

  1. Sometimes scientists are unable to find the exact gene that causes a disease, but they are able to find sections of DNA that are somehow linked to, and inherited alongside it
  2. It may be technically difficult to find the mutation and it may be easier and cheaper to look at and determine linked markers instead
  3. The test for a particular genetic mutation is patented by a specific laboratory and may not allow others to offer this test, or may ask that they pay to offer it. In these circumstances, some laboratories may create a linkage test so that they can offer the test to their clients
How are results recorded?
Health conditions which have a linkage test will still be either autosomal dominant or autosomal recessive. Currently we only accept results for autosomal-recessive conditions and so the information below relates to these only.

Breeders should be aware that linkage tests are not always 100% accurate and may not be definitive.

Tested dogs will be recorded on The Kennel Club's 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 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

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 knowingly increasing the risk of producing affected puppies. They can produce puppies that are carriers if they are bred with a carrier or affected dog.

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 which 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?
Clear dogs are only known to be clear for the condition that they have been tested for, and may carry other unknown mutations which can be passed on to their offspring - it is almost certain that all individuals carry some versions of genes that if inherited in duplicate would result in disease. If a particular dog has many offspring that go on to breed themselves, these unknown mutations may then increase in frequency in the breed and a new inherited disease could emerge. In other words, no dog is completely risk free, but there are ways a breeder can reduce the risk of known and unknown inherited disease. 
Additional cautions about using carriers or affected dogs

Sticking to these rules will mean that you can still use these dogs for breeding, while maintaining genetic diversity within the breed.

  • Never overuse a carrier or affected dog for mating. If a dog has one or two copies of a known faulty gene it should never be overused for breeding. Overusing these dog’s risks increasing the frequency of the faulty gene within the population, making it more difficult for future generations to breed without increasing the risk of producing affected dogs
  • Do your research. If all breeders decided to use carriers or affected dogs for mating, then there is a possibility that as the frequency of mutant genes increases, then the proportion of 'clear' dogs would decline. You can use carriers and affected, but you always want to make sure you have a big enough supply of clear dogs. You may wish to talk to health representatives at your local breed club who will have access to summary information on the results of dogs that have been DNA tested and can advise you appropriately on the current situation in your breed
  • Any possible carrier puppies that go on to be bred from should be DNA tested prior to mating. If you do decide to produce puppies that are potentially carriers, but are concerned that they may be used by their new owners for breeding, then you may wish to consider placing an endorsement on the puppy, or include a statement in your puppy contract that any puppies used for breeding must be tested prior to mating and if the puppy is a carrier, it must only be mated to a clear dog

Risk-based DNA tests (incomplete penetrance)

Most DNA tests look for a particular gene that is known to cause a particular condition. For some conditions, certain environmental factors, or other genetic influences can also contribute to whether a dog becomes affected. Having copies of the disease-causing genes will therefore not be a guarantee that the condition will occur. Similarly an absence of these genes will not be a guarantee that the condition will not occur.

These risk-based tests are sometimes not quite as accurate as other DNA tests, but can still be useful to breeders. Laboratories will often estimate how accurate their test is.

How are results recorded?
Health conditions which have a risk-based DNA test will still be either autosomal dominant or autosomal recessive. Currently we only accept results for autosomal-recessive conditions and so the information below relates to these only.

Tested dogs will be recorded on The Kennel Club's systems as at “minimal risk (0)”, “minimal risk (1)” or “increased risk (2)”. The numbers assigned to each status indicate the number of copies of the mutant gene variant a dog has.
  • Minimal risk (0) - these dogs do not have any copies of the abnormal gene associated with the condition that has been tested for. These dogs are at significantly reduced risk of developing the condition
  • Minimal risk (1) - these dogs have one normal copy and one abnormal copy of the gene associated with the condition that has been tested for. These dogs are at reduced risk of developing the condition and may pass either one copy of the normal gene, or one copy of the abnormal gene on to future puppies
  • Increased risk (2) - these dogs have two copies of the abnormal gene associated with the condition that has been tested for. These dogs have an increased risk of developing the condition
Breeding advice - if your dog is minimal risk (0)

These dogs can be mated to any dogs without increasing the risk of the puppies developing the condition tested for. Your chosen mate should always be tested and your decision should be informed by their results.

Minimal risk (0) x minimal risk (0)

Each puppy born has a:

  • 100% chance of having a minimal risk (0) status
  • 0% chance of having a minimal risk (1) status 
  • 0% chance of having an increased risk (2) status

This means that each puppy born will have the lowest chance of developing the condition and will not carry a copy of the gene variant tested for.

Minimal risk (0) x minimal risk (1)

Each puppy born has a:

  • 50% chance of having a minimal risk (0) status
  • 50% chance of having a minimal risk (1) status
  • 0% chance of having an increased risk (2) status 

This means that each puppy born will have the lowest chance of developing the condition, but will have a 50% chance of carrying a copy of the gene variant tested for. Dogs that are born minimal risk (1) could pass this gene variant on to any possible future puppies.

Minimal risk (0) x increased risk (2)

Each puppy born has a:

  • 0% chance of having a minimal risk (0) status
  • 100% chance of having a minimal risk (1) status
  • 0% chance of having an increased risk (2) status 

This means that each puppy born will have the lowest chance of developing the condition, but will carry a copy of the gene variant tested for and could pass this gene variant on to any possible future puppies they have.

Breeding advice - if your dog is minimal risk (1)

These dogs can be used for mating, but your chosen mate should always be tested and your decision should be informed by their results.

Minimal risk (1) x minimal risk (0)

Each puppy born has a:

  • 50% chance of having a minimal risk (0) status
  • 50% chance of having a minimal risk (1) status 
  • 0% chance of having an increased risk (2) status

This means that each puppy born will have the lowest chance of developing the condition and a 50% chance of carrying a copy of the gene variant tested for. Dogs that are born minimal risk (1) could pass this gene variant on to any possible future puppies.

Minimal risk (1) x minimal risk (1)

Each puppy born has a:

  • 25% chance of having a minimal risk (0) status
  • 50% chance of having a minimal risk (1)
  • 25% chance of having an increased risk (2) status 

This means that each puppy born has a 25% chance of possibly being affected by the condition.

Each puppy will also have a 75% chance of carrying at least one copy of the gene variant tested for. Dogs that are minimal risk (1) could pass this gene variant on to any possible future puppies, while dogs that are increased risk (2) will pass this gene variant on to any future puppies.

Minimal risk (1) x increased risk (2)

Each puppy born has a:

  • 0% chance of having a minimal risk (0) status
  • 50% chance of having a minimal risk (1)
  • 50% chance of having an increased risk (2) status 

This means that each puppy born has a 50% chance of possibly being affected by the condition.

Each puppy will also carry at least one copy of the gene variant. Dogs that are born minimal risk (1) could pass this gene variant on to any possible future puppies, while dogs that are born increased risk (2) will pass this gene variant on to any future puppies.

Breeding advice - if your dog is increased risk (2)

These dogs can be used for mating, but your chosen mate should always be tested and your decision should be informed by their results.

Increased risk (2) x minimal risk (0)

Each puppy born has a:

  • 0% chance of having a minimal risk (0) status
  • 100% chance of having a minimal risk (1) status 
  • 0% chance of having an increased risk (2) status

This means that each puppy born will have the lowest chance of developing the condition, but will carry a copy of the gene variant and could pass this gene variant on to any possible future puppies they have.

Increased risk (2) x minimal risk (1)

Each puppy born has a:

  • 0% chance of having a minimal risk (0) status
  • 50% chance of having a minimal risk (1)
  • 50% chance of having an increased risk (2) status 

This means that each puppy born has a 50% chance of possibly being affected by the condition.

Each puppy will carry at least one copy of the gene variant tested for. Dogs that are born minimal risk (1) could pass this gene variant on to any possible future puppies, while dogs that are born increased risk (2) will pass this gene variant on to any future puppies.

Increased risk (2) x increased risk (2)

Each puppy born has a:

  • 0% chance of having a minimal risk (0) status
  • 0% chance of having a minimal risk (1)
  • 100% chance of having an increased risk (2) status 

This means that each puppy born has a 100% chance of possibly being affected by the condition.

Each puppy will carry two copies of the DM risk gene variant and will pass one of these on to any future puppies.

Potentially producing affected puppies
A mating which may produce affected puppies could have a serious impact on their welfare. If this mating 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 they be at increased risk
  • 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?
Clear dogs are only known to be clear for the condition that they have been tested for, and may carry other unknown mutations which can be passed on to their offspring - it is almost certain that all individuals carry some versions of genes that if inherited in duplicate, would result in disease. If a particular dog has many offspring that go on to breed themselves, these unknown mutations may then increase in frequency in the breed and a new inherited disease could emerge. In other words, no dog is completely risk free, but there are ways a breeder can reduce the risk of known and unknown inherited disease.
Additional cautions about using carriers or affected dogs

Sticking to these rules will mean that you can still use these dogs for breeding, while maintaining genetic diversity within the breed.

  • Never overuse a carrier or affected dog for mating. If a dog has one or two copies of a known faulty gene it should never be overused for breeding. Overusing these dogs risks increasing the frequency of the faulty gene within the population, making it more difficult for future generations to breed without increasing the risk of producing affected dogs
  • Do your research. If all breeders decided to use carriers or affected dogs for mating, then there is a possibility that as the frequency of mutant genes increases, then the proportion of 'clear' dogs would decline. You can use carriers and affected, but you always want to make sure you have a big enough supply of clear dogs. You may wish to talk to health representatives at your local breed club who will have access to summary information on the results of dogs that have been DNA tested and can advise you appropriately on the current situation in your breed
  • Any possible carrier puppies that go on to be bred from should be DNA tested prior to mating. If you do decide to produce puppies that are potential carriers, but are concerned that they may be used by their new owners for breeding, then you may wish to consider placing an endorsement on the puppy, or include a statement in your puppy contract that any puppies used for breeding must be tested prior to mating and if the puppy is a carrier, it must only be mated to a clear dog

X-linked DNA tests that are dominant in males and incomplete dominant in females

The X-chromosome helps to determine a dog’s sex.

Male dogs only have one X-chromosome, which they always inherit from their mother. Females have two X-chromosomes, which they inherit from both their mother and father.

In females, the disease acts as an incomplete dominant trait, i.e. if a female only has one copy of the faulty gene and one healthy copy of the gene, her health will be affected, but not as severely as if she had two copies of the gene.

In males, because they only have a single copy of the X chromosome, the condition is dominant and they are either healthy (they only have a healthy copy of the gene), or severely affected (they only have the faulty copy of a gene).
How are results recorded
Dogs that have been tested for this condition can be described as either: clear, single affected or double affected (females only). It is advised that you speak to your vet about the results of this test to determine how this condition may affect your dog.

Clear
If your dog is clear they will not have any copies of the faulty gene associated with the condition you've tested for and will only pass on a normal copy of the gene to any offspring.

Single affected
A single affected male will have one copy of the faulty gene, which he inherited from his mother. These dogs are likely to be severely affected by the disorder. If bred from, single affected males will pass a copy of this abnormal gene to all female puppies, causing them to become affected. They will not pass the abnormal gene to their male puppies.

Females can have two copies of the X chromosome. A single affected female will have one healthy and one faulty version of the gene associated with the condition you've tested for. The dog is likely to be affected by the condition, although the severity varies between individuals. When bred from, a single affected female has a 50 per cent chance of passing the faulty gene to each of her puppies and so can produce affected puppies.

Double affected
A double affected female has two copies of the faulty genes, one inherited from her mother and one from her father. These dogs are likely to be severely affected by the disorder. If bred from, double affected females will pass on a copy of this abnormal gene to all of their offspring and so will produce affected puppies.
Breeding advice
The decision you make when choosing which dogs to mate must be informed and carefully planned.

If the health status of both sire and dam are known, the likely health status of any puppies produced can be predicted.

Please use the following table to note the outcome of mating a male and female with a known hereditary status:

  Clear male Single affected male
Clear female All puppies will be clear. All male puppies will be clear.

All female puppies will be single affected.
Single affected female Each male puppy will have 50% chance of being single affected.

Each female puppy will have 50% chance of being single affected.		 Each male puppy will have a 50% chance of being single affected.

Each female puppy will be affected, but they will have a 50% risk of being single affected and a 50% risk of being double affected.
Double affected female All male puppies will be single affected.

Each female puppy will be single affected.		 All male puppies will be single affected.

All female puppies will be double affected.

Breeding advice: If your dog is clear

Clear dogs should only be mated to other clear dogs. All other matings may produce affected puppies and so should not be carried out.

Breeding advice: If your dog is affected (either single or double)

Your dog should not be bred from. Mating this dog could produce affected puppies. Producing affected puppies could have a serious impact on their health and welfare. A mating which 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.

 

Are clear dogs 100% clear?
Clear dogs are only known to be clear for the condition that they have been tested for, and may carry other unknown mutations which can be passed on to their offspring - it is almost certain that all individuals carry some versions of genes that if inherited in duplicate would result in disease. If a particular dog has many offspring that go on to breed themselves, these unknown mutations may then increase in frequency in the breed and a new inherited disease could emerge. In other words, no dog is completely risk free, but there are ways a breeder can reduce the risk of known and unknown inherited disease.

X-linked DNA tests that are dominant in males and recessive in females

The X-chromosome helps to determine a dog’s sex.

Male dogs only have one X-chromosome, which they always inherit from their mother. Females have two X-chromosomes, which they inherit from both their mother and father.

In females, the disease acts in a recessive way, i.e. a female must inherit two copies of the faulty gene (one from her mother and one from her father) to be affected.

In males, because they only have a single copy of the X chromosome, the condition behaves as if it were dominant and male dogs are either healthy (they only have a healthy copy of the gene) or affected (they only have the faulty copy of a gene).
How are results recorded?
Dogs that have been tested for this condition can be described as either: clear, carrier (females only) or affected.

Clear
If your dog is clear they will not have any copies of the faulty gene associated with the condition you've tested for and will only pass on a normal copy of the gene to any offspring.

Carrier
Carriers have one healthy and one faulty version of the gene associated with the condition you've tested for. Only females can have two copies of the X chromosome, and so only females can be carriers for the condition you've tested for. Despite carrying one copy of the faulty gene, the dog is unlikely to be affected by the condition. When bred from, a carrier has a 50 per cent chance of passing the faulty gene on to her puppies.

Affected
A female with two copies of the faulty genes, one inherited from her mother and one from her father, will be affected. Affected males will have a single copy of the faulty gene, which he inherited from his mother.

If bred from, affected females will pass on a copy of this abnormal gene to all their offspring. Any male puppies that inherit the faulty gene will be affected.

Affected males can only pass this faulty gene on to female puppies.

It is advised that you speak to your vet about the results of this test to determine how this condition may affect your dog.
Breeding advice
The decision you make when choosing which dogs to mate must be informed and carefully planned.

If the health status of both sire and dam are known, the likely health status of any puppies produced can be predicted.

Please use the following table to note the outcome of mating a male and female with a known hereditary status:

  Clear male Affected male
Clear female All puppies will be clear. All male puppies will be clear.

All female puppies will be carriers.
Carrier female Each male puppy will have 50% chance of being affected.

Each female puppy will have 50% chance of being a carrier		 Each male puppy will have a 50% chance of being affected.

Each female puppy will have a 50% risk of being a carrier and a 50% risk of being affected.
Affected female All male puppies will be affected.

All female puppies will be carriers.		 All puppies will be affected. 

Breeding advice: If your dog is clear

Clear dogs should only be mated to other clear dogs. All other matings may produce affected puppies and should not be carried out.

Breeding advice: If your dog is a carrier or affected

Your dog should not be bred from. Mating this dog could produce affected puppies. Producing affected puppies could 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 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. 

Are clear dogs 100% clear?
Clear dogs are only known to be clear for the condition that they have been tested for, and may carry other unknown mutations which can be passed on to their offspring - it is almost certain that all individuals carry some versions of genes that if inherited in duplicate would result in disease. If a particular dog has many offspring that go on to breed themselves, these unknown mutations may then increase in frequency in the breed and a new inherited disease could emerge. In other words, no dog is completely risk free, but there are ways a breeder can reduce the risk of known and unknown inherited disease.