Over the past 9,000 years, American black bear fur has evolved a cinnamon color

WASHINGTON – A number of black bear America (Ursus americanus) to the west United States of America (USA) evolved to have cinnamon colored fur. This new brownish hue likely arose from a genetic variant similar to the cause of albinism in humans.

Researchers from the United States and Japan analyzed DNA samples from 151 American black bears in the United States and Canada. They found that most American black bears living in states like Nevada, Arizona and Idaho were more likely to exhibit reddish coats than black fur.

Researchers have identified a mutation known as R153C in a gene called tyrosinase-related protein 1 (TYRP1). This genetic mutation causes a change in the pigmentation of the fur which gives the bear a color similar to a copper coin.

Read also; This is why polar bears are not found in Antarctica

“TYRP1 is a pigmentation gene recognized in the molecular precursor pathway that ultimately produces eumelanin (a black or brown pigment) or pheomelanin (a red or yellow pigment),” said Emily Puckett, assistant professor of biological sciences at the University of Memphis Tennessee. Live Science Monday (12/19/2022).

Over the past 9,000 years, the American black bear has slowly turned red due to a genetic variant. According to studies of the cinnamon (fur) variant, which Puckett called a mutation that appeared about 9,360 years ago, gradually spreading throughout the population.

The researchers also examined whether the development of this gene in American black bears is related to thermoregulation. A mechanism that helps mammals regulate body temperature or competes with other cinnamon bear species, such as the brown bear (Ursus arctos), also known as the grizzly bear.

“We tested thermoregulation and competition with brown bears, and neither was strongly supported. Our new hypothesis is that it’s a selective advantage mechanism,” Puckett said.

Read also; Alaskan bears forced to eat grass, concerned about declining salmon populations

Interestingly, this variant is similar to the one in humans known as oculocutaneous albinism type 3 (OCA3). This condition causes the hair and skin to be lighter in color, two hallmarks of albinism.

In some cases, it can also cause vision problems. “What’s interesting is that the bear hasn’t shown any visual signs of a problem,” Puckett said.

(wib)