There’s much discussion in the Airedale Terrier community – and other breed communities, for that matter – about white markings on the chest, toes, or tail tip – often seen as imperfections. But before we rush to exclude these dogs from our gene pool, let’s take a closer look at what these markings represent and why excluding such dogs might be doing more harm than good.

Colour Genetics of Airedales

Airedale Terriers coat colour is primarily controlled by the agouti (A locus) gene, which controls the distribution of dark (black) and light (tan) pigmentation. The A locus is located on chromosome 24 in dogs, very close to the RALY gene, which has been identified to affect the saddle tan pattern.

In many breeds, the S locus controls white spotting and involves genes like MITF and KIT that regulate pigment distribution. However, in Airedales, the S locus is not associated with the small residual white patches occasionally seen on the toes, chest, or tail tip. Instead, residual white is believed to occur due to the incomplete migration of pigment cells in the early stages of development rather than to the genetic mechanisms responsible for more extensive white spotting seen in other breeds.

What is Residual White?

During early development, all mammals, including dogs, start as genetically “white.” Pigmentation occurs as melanocytes (pigment-producing cells) migrate to various parts of the body. Occasionally, this migration is incomplete, resulting in small, unpigmented areas, typically on the chest, toes, or tail tip.

Residual white can occur for several reasons and sometimes linked to minor environmental factors during pregnancy, while other times it appears randomly. These markings are relatively common and can vary in size and location, depending on a dog’s genetic makeup, but they don’t indicate any health or functional issues.

Although some dogs may seem predisposed to these markings, there’s no known inheritance pattern for residual white, meaning we can’t predict whether a dog will pass it on to its offspring. So, should these markings really be a reason to exclude a dog from breeding? 

Think about it: Does a small white patch impact a dog’s health, temperament, or ability to perform? The answer is no. Residual white doesn’t affect these important qualities. So why do we place so much importance on something that most likely doesn’t matter in the long run?

The Russian Fox Experiment: Could White Markings Link to Temperament?

In the Russian Fox Experiment, researchers bred wild foxes for tameness. Over generations the foxes became more friendly, but they also developed physical changes including floppy ears, curly tails, and white patches on their fur. These traits appeared as a side effect of selecting for temperament.

This raises an interesting question: Could residual white in dogs be linked to temperament? There’s no clear evidence that white markings in Airedale Terriers influence behaviour, but the fox experiment shows that traits like white patches can emerge alongside behavioural changes during the domestication process. In dogs, residual white could simply be a natural by-product of domestication and genetic variation, as seen in many breeds today.

It’s worth noting that the old Ridgeback breeders often said that residual white should never be bred out, as they believed it was linked to temperament. Could there be some truth to this, and could it also apply to Airedales?

The Genetic Crisis in Airedale Terriers

Airedale Terriers are already facing a genetic bottleneck, with a Genetic Coefficient of Inbreeding (gCOI) on average of 38%, according to Embark – an alarmingly high number. This shrinking gene pool directly results from inbreeding, and excluding dogs for minor traits like white markings will only worsen the situation.

Are we willing to risk the future health of our breed for the sake of minor cosmetic features? By focusing too heavily on cosmetic traits, we risk losing genetic diversity, which increases the chances of hereditary health issues. In fact, we are already seeing signs of lost genetic diversity in the breed, and health problems are beginning to emerge.

And no, breeding dogs with small residual white patches won’t turn Airedales solid white. The risk of white spreading throughout the gene pool is minimal. These markings occur sporadically and are not heavily inherited, and the number of dogs bred with residual white will likely be too small to have any significant impact. If residual white is indeed polygenetic or influenced by incomplete penetrance, it’s even less likely that the trait will become widespread in the breed.

So, Should We Breed Dogs with Residual White?

The short answer is yes, as long as the dog is healthy, structurally sound, and has a good temperament. Breeding dogs with residual white can help preserve genetic diversity, which is critical for the long-term health of the breed. In fact, these white patches are likely a natural part of the breed’s genetic variation and should not be dismissed lightly.

That said, it’s understandable that some breeders want to adhere to breed standards, which may limit the amount or placement of white markings. The key is finding a balance between preserving the breed’s conformation and ensuring genetic health. Instead of focusing primarily on aesthetic traits, we should place greater emphasis on what truly matters, which I’m sure everyone agrees is maintaining the breed’s health, temperament, and functionality to ensure its vitality for generations to come.

Diversity for a Sustainable Future

White markings are a natural part of the genetic landscape in Airedale Terriers. In a breed where genetic diversity is already at risk, excluding dogs based on minor superficial traits like white patches is not only unnecessary, but it also poses a threat to the breed’s health. Do we want to be the generation that narrows the gene pool further by chasing superficial standards? Or the generation that ensures a healthier, more resilient breed for the future?

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Note: This text was initiated and written by the author, with AI tools used to enhance language and readability. The featured photo is AI created. 
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