Although we do not breed for colour, understanding coat genetics is a powerful tool in managing the health of our puppies, so we are more than a little bit obsessed with the fascinating science behind coat colour genes and how we can use them to safely plan our future generations.
The most important thing about understanding coat colour genes is reducing the risk, (if not entriely eliminating) colour related health conditions such as Colour Dilution Alopecia. CDA is a painful inherited condition that causes patches of hair thinning or loss and can mean a lifetime of flaky, itchy skin. The condition is associated with the “dilute” gene, most commonly seen in dogs with a blue coat. DNA screening has shown that we have a few dogs who are recessive carriers. This is where understanding coat genetics is critical. By knowing who carries what, we are able to breed away from it and eliminate the risk by ensuring we select carefully and don't double up on the dilute gene.
Another nasty, resessive condition we test for is Black Hair Follicular Dysplasia, which causes permanent hair loss. Pups affected with BHFD are affected very early in life, usually around one month old, and get progrssively worse. Generally, all hair is lost in black colored areas of the puppy's coat by 8 to 9 months of age. leaving them highly susceptible to bacterial skin infections for the rest of their life.
Who wouldn't do everything in their power to stop a poor dog being inflicted with that for it's whole life?
Knowing our dogs' coat genetics also has a more mundane, practical application. When we get enquiries from prospective owners who absolutely must have a particular colour from an upcoming litter, it's pretty easy to tell them whether it's likely.
For example, if we mated AyAy Ren (a fawn sable) to AtAt Alice (our gorgeous black and tan girl) we know we'd only get fawn-sables, because we know that's all Ren's genes allow him to produce. Alice's black and tan markings come from her having two copies of the recessive AtAt genes. Because the black and tan gene is recessive, she can only produce pups the same colour as herself if the father also adds his recessive "At" gene to the mix. Ren is AyAy, so no black and tan gene, ergo, no black and tan puppies.
If we mated Alice to Narci, however, then we're likely to get all sorts of interesting colors and markings, because of Narci's more varied coat genetics.
You can see Ren's dominant genes in action in our most recent litter (the famous Friday 13th pups). Their mother is Bubbles, who is "AyAt" - a gold and white girl with the distinctive "Irish" markings (white chest and collar). Despite her lovely markings, Ren's AyAy genes have prevailed (as they must) and our babies are all variations of his fawn-sable colouring. They will lighten as they grow older to be closer to the colour of their dad.
The other advantage of knowing their coat genetics so well, is that if these puppies had popped out any other colour than fawn-sable, we'd have known instantly that we had a problem, LOL!
As part of the Accredited Breeders Scheme in NZ, breeders are required to pass an examination on genetics, so more and more breeders are coming to understand what a powerful weapon coat genetics are, in the fight for healthier puppies and the elimation of health conditions that can be carried on from one generation to the next.
Paw Print Genetics have produced this excellent chart which shows the Base Coat Colour Flowchart.
If you really want a deep dive into coat genetics, we highly recommend this online seminar by Dr Casey Carl DVM on Canine Modifying Coat Colours and Traits. Be warned, though, you may end up as obsessed with coat gentics as we are!