Black Wolves Have Dogs to Thank

Allison Guy
November 29th 2011

Black wolves should probably not exist. The same species as their gray relatives, these wolves have a genetic mutation that causes them to produces excess melanin, a pigment responsible for coat color. The origin of black wolves has long been a puzzle. Unlike domestic animals, wild species usually don't exhibit such dramatic variations in coloration, especially within the same population. While all tigers are orange and striped, and all grizzly bears are brown, "gray" wolves range from pure white to brown to red to black.

Researchers at Stanford University have discovered that dogs may be the cause of the wolves' unusual coloration. Dogs have a unique gene for melanism, which is also shared by European, Asian and American black wolves. Scientists estimate that the gene arose somewhere between 12,779 and 121,182 years ago, with a preferred time of around 50,000 years. Even if European wolves were the first to don a black coat, it was domestic dogs that brought the gene to the wolves (and coyotes) of North America.

Most new mutations tend to disappear within a few generations. With North American wolf, however, this accidental genetic loaner from dogs has become a stable part of their population's DNA. Clearly, black wolves derive some benefit from their coloration. The reasons why are still a mystery: Black coat color doesn't aid in camouflage, but since it occurs more frequently in southern, forest-dwelling wolves, it may have some advantage for life in warmer climates.

The melanism gene in wolves is one of the few instances, perhaps even the only instance, in which interbreeding with a domestic animal has conferred an adaptive edge on a wild animal. As climate change progresses, and forests march northward, it may be that the "gray" wolf population will soon switch to black, all thanks to some melanistic, prehistoric pooches.

Via the New York Times. Image via Carnivora.

Share your thoughts and join the technology debate!public: 1


Miss Cellany
Posted 29/05/2014 – 00:16

"You say that wolves got the gene from dogs, but how would that be if it’s already been proven that all dogs are derived from wolves? Sorry but to me it just doesn’t make sense."
Dogs picked up lots of mutations during the process of domestication from wolves -> dogs (domestication actually produces many changes in phenotype - look up silver fox domestication experiments).
Dogs then bred back into wild wolf populations (accidentally, no one did this on purpose I think!) and the mutation for black fur was introduced into wolf populations. Over time, the prevalence of the mutation rose as apparently it confers some small advantage (heat loss is my guess).
It makes perfect sense, its probably happened with other species too (black European wildcats for e.g.)

Miss Cellany
Posted 29/05/2014 – 00:10

"Is it possible that these wolves derived their black coats from a mutation similar to that of blue eyes in humans?"
Yes its possible that that is how it happened in Asiatic wolves (the population that gave rise to dogs), but the article points out that the mutations are the same across all wolf populations which means it was carried there by dogs (Wolves cannot cross the oceans on their own!).
I personally think all black wolves are carrying dog genes as its more likely that the color arose during the domestication process (when a load of other mutations also occurred).
The advantage conferred is probably something to do with heat loss as black coats / feathers lose heat faster than other colors in warm climates (why the Bedouin wear black in the desert!).

Posted 16/07/2012 – 10:18

You say that wolves got the gene from dogs, but how would that be if it's already been proven that all dogs are derived from wolves? Sorry but to me it just doesn't make sense.

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