# Does the coat color effect health?



## cowpony (Dec 30, 2009)

White and cream poodles are not at risk of the problems found in other white dogs. I've got a lengthy explanation below. Red poodles may or may not be at risk of problems caused by inbreeding. It really depends on whether the breeder is being careful. It's harder to breed a good red, because red is a recessive trait. You can only get red by breeding to another red carrier. Therefore, to maximize the number of red dogs in each litter, it is very tempting for a breeder to keep breeding red to red without ever outcrossing. You can see how this might eventually lead to problems. A good breeder will always do outcrosses to broaden the genetic diversity of her kennel.

Now, about white dogs, merle dogs, and why they can have problems. Pigment producing cells called melanocytes are normally found in the skin, eyes, inner ear, and other body tissues. These cells are generated very early in the fetus from the neural crest and move to their proper position as part of fetal development. Various causes, both genetic and environmental, can interrupt the proper formation and migration of these neural crest cells. When the cells fail to migrate properly, the organs where they were supposed to be located develop incorrectly. Eyes, ears, intestines, etc. may be malformed and partially or completely non-functional. Skin and hair normally show white patches and mottling.

There are a multitude of diseases in many different species which are related to issues with the development and migration of neural crest cells. In humans there is something called Waardenburg syndrome. People with the syndrome may have one or two blue eyes, a white forelock or prematurely greying hair, partial albinism, deafness, widely spaced eyes, and/or problems with gut motility. Turkish Van cats are known for having one or two blue eyes, mostly white fur, and often partial or complete deafness. A single copy of the Overo gene in horses leads to white spots and sometimes one or two blue eyes; two copies of the Overo gene (aka Lethal White) produces a completely white foal that will die within days from gut malformations.

Similar things can happen in dogs. Unfortunately, we think the white spots and mottling are pretty, and so we have actually selected for it in some cases. The most well known issues are with merle dogs and Dalmatians. Dogs with a single merle gene have mottled coloring and one or two blue eyes; double merle dogs commonly have malformed eyes and deafness. Dalmatians are well known for their white coats with spots. However, Dalmatians sometimes also have blue eyes and/or deafness in one or two ears.

As for poodles, yes, the genetics of double merle work the same way in poodles as in any other dog. That's one reason so many poodle fanciers are so hostile to merle breeders. However, a white or cream poodle is not normally at risk of the problems associated with mottled white coloring. The melanocytes in a white poodle migrated to where they belong and are acting normally. A white poodle is the equivalent of a platinum blond in humans. White poodles, just like a blond human, have normal colored skin under the pale hair. The dog will get a suntan when he goes out in the sun, just like a blond human will get a suntan. White poodles normally have brown eyes, just like any other poodle.

Edited - I got the name of Waardenburg Syndrome slightly wrong and have corrected it above. My apologies, especially to the Waardenburg community members, who deserve more carefulness from me.


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## Footprints&pawmarks (Mar 8, 2021)

Great explanation, thanks!


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## Sylvia K (Feb 4, 2021)

cowpony said:


> White and cream poodles are not at risk of the problems found in other white dogs. I've got a lengthy explanation below. Red poodles may or may not be at risk of problems caused by inbreeding. It really depends on whether the breeder is being careful. It's harder to breed a good red, because red is a recessive trait. You can only get red by breeding to another red carrier. Therefore, to maximize the number of red dogs in each litter, it is very tempting for a breeder to keep breeding red to red without ever outcrossing. You can see how this might eventually lead to problems. A good breeder will always do outcrosses to broaden the genetic diversity of her kennel.
> 
> Now, about white dogs, merle dogs, and why they can have problems. Pigment producing cells called melanocytes are normally found in the skin, eyes, inner ear, and other body tissues. These cells are generated very early in the fetus from the neural crest and move to their proper position as part of fetal development. Various causes, both genetic and environmental, can interrupt the proper formation and migration of these neural crest cells. When the cells fail to migrate properly, the organs where they were supposed to be located develop incorrectly. Eyes, ears, intestines, etc. may be malformed and partially or completely non-functional. Skin and hair normally show white patches and mottling.
> 
> ...


 Thanks for the detailed information! It's very helpful and has now got me wondering. I have several of the Van Waardenburg symptoms mentioned - two blue eyes, a largish white swathe of hair at the right side of my brow. The white swathe developed several years ago and has never spread to any other area. My hair colour everywhere else is very fair. I am profoundly deaf in my right ear and have limited hearing in my left ear. I feel for any animals, or other person, with this condition. I don't think at my advanced age I shall bother about following it up but it's certainly something that could give answers to many questions I've had. I've never had an animal that exhibited any of those symptoms, although I did have one toy poodle who lost his hearing as he aged. I think that was just part of the ageing thing though. It didn't seem to bother him, but it concerned me in case he ever got out onto the road because he may not have heard the traffic. Luckily that never happened. I think I was too paranoid about the possibility and became super aware of everything in the environment that could have been a threat to his safety.

I am interested in colour genetics and did a bit of research on this when we got our latest poodle, a very dark chocolate brown miniature. It seems to be a whole branch of genetics on its own! Very complex and interesting. I have sometimes wondered about the hostility towards merles but reading this explanation I can understand why. Anyway, many thanks for all the detail.


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## toypoodle_lover (10 mo ago)

cowpony said:


> White and cream poodles are not at risk of the problems found in other white dogs. I've got a lengthy explanation below. Red poodles may or may not be at risk of problems caused by inbreeding. It really depends on whether the breeder is being careful. It's harder to breed a good red, because red is a recessive trait. You can only get red by breeding to another red carrier. Therefore, to maximize the number of red dogs in each litter, it is very tempting for a breeder to keep breeding red to red without ever outcrossing. You can see how this might eventually lead to problems. A good breeder will always do outcrosses to broaden the genetic diversity of her kennel.
> 
> Now, about white dogs, merle dogs, and why they can have problems. Pigment producing cells called melanocytes are normally found in the skin, eyes, inner ear, and other body tissues. These cells are generated very early in the fetus from the neural crest and move to their proper position as part of fetal development. Various causes, both genetic and environmental, can interrupt the proper formation and migration of these neural crest cells. When the cells fail to migrate properly, the organs where they were supposed to be located develop incorrectly. Eyes, ears, intestines, etc. may be malformed and partially or completely non-functional. Skin and hair normally show white patches and mottling.
> 
> ...


Thank you for the explanation this will help me a lot at picking the right poodle


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