There are a number of DNA tests which breeders should be utilising when selecting breeding stock. Dogs don't necessarily have to have a clear DNA test result for breeding, however when selecting breeding combinations, every effort should be made to avoid producing dogs affected by the relevant conditions.
When breeding dogs with 1 copy of any gene MUST only be bred to a dog who is clear for the same gene. (MDR1 is an exception to this rule.)
MDR1 – Multi Drug Resistance
HSF4 – Hereditary Cataracts
This is a form of Cataract, which develops in the posterior region of the lens and is bilateral to both eyes. It often develops whilst the dog is still young, but not always. These cataracts tend to start off small and grow over a period of time.
HSF4 is a dominant trait with incomplete penetration. This means having 1 copy of the gene greatly increases a dogs chances of developing cataracts, but doesn’t mean it will go on to develop them.
(Please note there are more than 1 type of cataracts in the breed, this test is only for one specific type)
CEA – Collie Eye Anomaly
CEA is an eye condition. In dogs with CEA, there are abnormalities of the choroid layer of the eye (under the retina) and may also be changes in the sclera. The major change, which is present in all dogs with CEA, is 'choroidal hypoplasia', a pale patch in the back of the eye caused by abnormal development of the choroid layer. Affected dogs may also have abnormalities in the sclera, producing pits or 'colobomas' in or around the optic disk. Dogs can be affected to different levels, but in dogs affected with CEA it can lead to retina detachment and blindness. Other dogs may only have mild symptoms, and some may even appear to have normal eye as an adult in a routine eye test, but is usually picked up in a puppy eye test. Due to this ability to ‘go normal’ it is important to use DNA testing as a tool in a breeding programme.
To be affected by CEA a dog needs to have 2 copies of the gene.
PRA – Progressive Retinol Atrophy
As its name suggests this is an eye condition linked to the Retina. With PRA the cells in the retina die off, leading to the dog becoming blind.
To be affected by PRA, a dog needs to have 2 copies of the gene.
CD – Cone Degeneration
This is another eye condition. The Retinal Cones which respond to light degenerate causing ‘day blindness’. Dogs as young as 8 weeks, can start to show sensitivity to bright light, due to the day blindness. Their vision is not affected by dim light.
To be affected by CD a dog needs to have 2 copies of the gene
CRM1 - Canine Multifocal Retinopathy
This is a condition affecting the retina of the eye. If a dog is affected for CMR1 it causes lesions to form on the retina. Lesions may disappear or cause some minor folding of the retina. The dogs sight is not usually effected.
To be affected by CD a dog needs to have 2 copies of the gene.
DM – Degenerative Myelopathy
DM is a progressive neurological disorder than effects a dogs spinal cord. Dogs will first show symptoms with an unsteady gait which over time weakens the hind legs, to a point where the dog is unable to walk. The condition will gradually progress up the dogs spinal cord affecting other areas of the body as well.
A dog with 2 copies of the gene is at a high risk of developing DM. There is a small risk that dogs with 1 copy of the gene will develop symptoms.
HUU – Hyperuricosuria
Dogs affected with HUU have a high acidity in their urine. Over time this can form hard stones in the bladder. Which if they move through the urinary tract can be painful. Dogs with HUU may have difficulty or a high frequency of urinating. If the stones can not move through the urinary tract, this can lead to operations to have them removed and other complications.
To be affected by HUU dogs need to have 2 copies of the gene.
NCL - Neruronal Ceroid Lipofuscinosis
This is where the cell functions don’t work properly and can lead to some chemicals building up in the cells that can be toxic, especially to nerve cells. This can lead to degeneration of the brain and eye, resulting in neurological impairment, and an early death.
To be affected by NCL dogs need to have 2 copies of the gene.
Nb. If testing with Laboklin, the NCL test is for NCL 6, the Combi package covers NCL 6 & 8.
This is where dogs are unable to absorb vitamin B12 from their food through the stomach lining. This can be related to a number of different conditions, but there can also be a genetic link. Dogs who fail to absorb B12 can go on to display symptoms of other diseases.
To be affected with Cobalamin Malabsorption, dogs need to have 2 copies of the gene.
For all health conditions we have DNA tests for a dog will inherit one copy of the gene from each parent.
See the table below to see what different breeding combinations will produce. At all times when breeding the aim must be to not be producing affected dogs.
UK Based Labs
There are a number of UK based labs that carry out DNA testing, below is a list of some of them in alphabetical order. There are a number of other labs that carry out the tests as well
Animal DNA Diagnostics - https://www.animaldnadiagnostics.co.uk
Animal Genetics UK - https://www.animalgenetics.eu *
Kennel Club Combibreed - https://www.thekennelclubshop.org.uk/products/combibreed-health-test-packages
Laboklin - http://www.laboklin.co.uk
* ASCUK members can receive a 20% discount off the full Aussie Panel (CEA, HSF4, MDR1, CMR1, CD, DM, PRA-prcd, HUU is also included with the discount code) if using Animal Genetics UK. Please contact Jayne Holligan for more information.