Blue Eyes

Blue eyes: you love them or you hate them! There seems to be a great divide amongst people when it comes to the striking gaze of a blue-eyed dog. Some people are off-put by the intensity while others thoroughly love that "White Walker" stare! Blue eyes is a fairly rare phenomenon in dogs over all. Let's break it down on this page!

There are some dogs out there that have blue eyes due to the pigment dilution from being Merle. The merle gene is like throwing bleach at a blanket and where ever it lands the colour in that spot is disrupted - the pigment is diluted. This is what gives merle dogs that marbled look and no two are the same. When that "bleach" affects the eyes the original pigment is changed to blue. In a merle dog, this could result in solid blue eyes or eyes that look marbled as some parts remain the original, genetic colour and others parts are modified to blue. There are very few instances of "regular merle" (M/m genotype) of having any eye abnormalities and it is not considered something to worry about when breeding for normal merle dogs. However, when two merle dogs are bred there is a 25^% chance that the offspring inherit two of the dominant M genes - one from each parent - which produces a "Double Merle". These M/M dogs have a high risk of eye and ear abnormalities/disabilities as the genes responsible for the pigment disruption also disrupt the pigment in the eye and ear cells. Doubling up on this can lead to cells in the eyes and ears being abnormal which leads to various forms of vision and hearing impairment. It is important to note that, even though the internet INSISTS that Double Merle dogs have all kinds of other health issues due to being M/M, it's not accurate information. The belief stems from people who acquire M/M dogs, who also see other health issues and/or behaviour issues. This however, is an example of 'correlation does not equal causation'. It is true that some M/M dogs out there are a result of good breeders having an accident between two totally healthy, well adjusted dogs. When you have been breeding for long enough an accident is going to happen one day and two dogs you didn't want together made other plans. Every single breeder I know has had an oops. Whether they terminated the litter or decided to just go through with it, is up to each breeder. I have had an accident breeding and it was between two merle dogs. Yes, I ended up with two double merle pups in that litter and both had a bit of disability with vision impairment and being stone deaf. They have AMAZING lives and the most lovely temperaments and are otherwise completely healthy (almost 6 years old at the time of this article). However, a good bulk of double merle dogs that end up on the planet are from people who have no idea what they are doing/breeding and/or are puppy mills that do not care. They breed merle to merle breedings on purpose to increase the chances of merle which is a colour that sells quite easily as it is so flashy. This type of breeding practice points to dogs that are ill tempered and unhealthy being bred for nothing other than a quick buck. So, this is the reason why there is a strong, yet scientifically inaccurate, consensus on the internet that double merle dogs are all genetic, sickly, poor tempered nightmares.

In other dogs with blue eyes the blue can be related to the White Spotting genes. It is not surprising to see dogs with a lot of white, especially on the head, to have blue eyes. This is directly related to the genes that are controlling the white patterning. It is not easy to predict when it will happen, and it's not ideal to see little to no pigment on the ears and around the eyes. In some instances "high white" can lead to vision and hearing issues but this phenomenon seems to also be linked in certain breeds or breed-types. For example: "white head" in Border Collies is linked to deafness. Not all of them with white heads will be deaf, but it is a noticeable trend in them with one study revealing that over 25% of Border Collies that had over 50% white on their heads were deaf. Other dog breeds that are predominantly white-headed - let's take the Old English Sheep Dog for example, a breed that is basically all white-headed - have less than 2^% instance of deafness. I am getting a little off track here, but circling back to blue eyes: blue eyes can also be the result of no pigment on the head.

Bernese Mountain Dogs with blue eyes: Yes! They do exist. The white on a Bernese Mountain Dog is a type of White Spotting called Irish Spotting. The Irish Spotting is the name for the specific traditional pattern of white "tuxedo" markings on the Bernese Mountain Dog. Rarely, there will be, for reasons not really predictably understood, a Bernese that will have one or two blue eyes. There is a connection to the pigment deletion from the white spotting, but it's more of a random thing that seems to just happen. It is not allowed for in the breed standard, so purebred Bernese Mnt. Dog breeders, that have it pop up here and there, will take extra steps to weed it out of their lines. It is quite stunning, in my opinion, and is NOT a health concern at all.

Now that we have all that out of the way.....

Blue Eyes in the Moonstruck program!
On Chromosome 18, near the ALX4 gene, there can be a special treat: a 98.6kb duplication can (and very often does!) lead to blue eyes!! This is a predicable, autosomal dominant gene that only requires one copy for expression (it's not 100%, but it's lots and lots). This type of blue eyes is only found naturally in Siberian Huskies and Australian Shepherds! Lucky for us we breed Aussie Mountain Doodles which, you guessed it, have some Aussie Shepherd in them! This is the origin of the non-merle factor blue eyes in the Moonstruck program as of 2026! This has been something I have been searching to add for many years, however, finding the right dog with this rare gene was not easy. As they say: "Good things come to those that wait." We waited and we have been rewarded with Denni (click on his name to learn all about this magnificent boy who has brought blue eyes to Moonstruck Bernedoodles!). Denni will pass blue eyes down to his puppies at a coin toss of 50/50 chance! Any colour of dog can inherit the blue-eyed gene and because it is a dominant gene, it will be very easy to keep it going for all the generations to come! Once we have our own pictures of blue-eyed Moonstruck dogs we will post them to this page as examples! For now, enjoy Denni's beautiful peepers!

Denni - click to see his page