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Thursday, 21 June 2012

Behind blue eyes

I have picked a male blue merle collie puppy out of a litter; they are currently five and half weeks old, and he has two bright blue eyes. Here is a photo of him:

I already have a blue merle dog who is two years old, and he has one blue and one brown eye. I have never seen a blue merle with two blue eyes; will they stay blue or will they go brown or wall eyed?

Sarah, Wigan


  1. If both parents of this puppy are merles, then you would be well advised to look elsewhere for a puppy. The puppy could be blind and/or deaf. That's why the Kennel Club has banned the mating of two merles , not only in collies. It's time people stopped thinking of merle and blue eyes as being attractive , and seeing it for what it is , a possible genetic hazard

    1. What a patronising and sweeping statement that is. Funny how the KC can be so opinionated on this matter, yet thoroughly endorse puppy farming and breeding of dogs that are related! It doesn't take two merles to make a merle and blue eyes don't necessarily mean problems. I'm sure this owner is just curious and already being a collie owner, has done their homework. I think they will stay blue and I think they are particularly attractive too.

  2. They'll change, 95% definite. Look at both the parents for an idea. Blue eyes are common in puppies but two blue eyes is very rare in an adult.

  3. They may stay, or they may go. Overall, it's of no great importance, as it has no impact on the health, temperament, or personality of your puppy.

  4. He is a lovely looking puppy. As the first poster says, make sure one parent is not merle or you may have issues later on.

    The merle gene is a genetic modification that causes the coat pattern to change and it also causes the pigmentation in the eyes to change, this can give blue, part blue eyes. It also causes the nose and paw pigmentation to change, hence the pink nose. The changes are random and it may be that your pup's eyes will change as he gets older and that his nose darkens. It also effects the colouring in the retina and can cause blindness.

    Merle dogs have a higher chance of being deaf as the gene also changes the colour of the hairs in the inner ear, if these are effected then the nerve ending will atrophy and die in the first few weeks of life.

    There are always two copies of a gene, alike or different, in any dog.

    One doze of the merle gene on an otherwise black dog will produce a merle. If we call the merle gene M and the non-merle gene m, any given dog can be mm, Mm or MM. The mm dog is the normal, full-colored dog. The Mm is a merle (blue, red ect) on what color it would have been without the merling gene. An MM dog, often called a double merle or a homozygous merle, will be mostly white and usually deaf or blind and often with other physical problems. Some MM puppies are born completely without eyes.

    Olwen Turns MADPT 1093