ome American black bears in the western US have evolved to have cinnamon-coloured fur. The new hue is likely due to a genetic variant similar to one that causes albinism in humans. Researchers from the US and Japan analysed DNA samples from 151 American black across the US and Canada and found that those residing in western states such as Nevada, Arizona and Idaho were more likely to exhibit reddish coats than the black fur for which the medium-sized bears are named. They identified a mutation known as R153C in a gene called tyrosinase-related protein 1 (TYRP1) that causes an alteration in the coat’s pigmentation that makes its fur the same colour as a copper penny. “TYRP1 is a known pigmentation gene that ultimately produces either eumelanin, black or brown pigment, or pheomelanin, red or yellow pigment,” , an assistant professor in biological sciences at the University of Memphis in Tennessee, said. “What it’s doing is changing the amino-acid sequence of that gene.” This ‘cinnamon variant’, which Puckett calls “a young mutation,” came about approximately 9,360 years ago and has gradually spread through the population.
