Scientists have followed the red fox's 400,000-year journey around the world, and created the first comprehensive genetic map of its evolutionary history, a new study describes.
The data, compiled from over 1,000 individuals from all over the world, exposes some surprising findings about the origins of the red fox, the world's largest land carnivore.
Until now, scientists had been studying the animal's genetic history by relying solely on information from its mother's side. Then researchers at the University of California (UC), Davis investigated ancestry across the red fox genome, including the Y chromosome, or paternal line. The results were striking.
"The genome and the information it contains about our ancestry and evolution is huge," lead author Mark Statham, an assistant project scientist with the UC Davis Veterinary Genetics Laboratory, said in a statement. "If you're only looking at what your mother's mother's mother did, you're only getting a small portion of the story."
Researchers had believed, based on this limited information, that red foxes of Eurasia and North America composed a single interconnected population across the Bering land bridge between Asia and Alaska. In reality, as this research shows, the red foxes of North America and Eurasia have been relatively isolated from one another for the last 400,000 years. During this time, the North American red fox evolved into a new species distinct from its Old World ancestors.
"That small group that got across the Bering Strait went on to colonize a whole continent and are on their own evolutionary path," Statham said.
The previous view was distorted by the maternal picture because a single female line transferred from Asia to Alaska about 50,000 years ago.
Given that ice sheet formation, fluctuating temperatures and changes in sea levels influenced the red foxes' journey, researchers believe this discovery could provide insight into how other species may have responded to climate change and other environmental shifts.
The findings were published in the journal Molecular Ecology,