Polar bears older than previously thought
New analysis reveals the Arctic species dates back about 600,000 years
Polar bears might have originated about 600,000 years ago, an international team reports April 20 in Science.
Previously, studies suggested that the polar bear, Ursus maritimus, emerged much later, about 150,000 years back. But many of these estimates were based on analyzing limited genetic information that’s passed down only through the maternal bloodline called mitochondrial DNA.
In the new study, researchers partially decoded DNA inherited from both parents from 45 bears, including polar, brown and black bears. Called nuclear DNA, this type of DNA carries the majority of an organism’s genetic instr
