The Red Fox is the most widely distributed land carnivore on Earth...........Historically, it has been assumed that Red Foxes found in Europe and North America were a single population interconnected by the Bering Land Bridge of Alaska/Asia ..............U. of California genetic testing has evaluated both male and female red fox ancestry and Researchers there are now postulating that American Red Foxes split from European Red Foxes 400,000 years ago, with American Red Foxes evolving into their own species............Ice Age conditions and subbsequent fluctuating temperature swings over time isolated the fox population in North America leading to their stand-alone species determination

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http://www.sciencedaily.com/releases/2014/10/141007144510.htm?utm_source=feedburner

ER ACTION "That small group that got across the Bering Strait went on to colonize a whole continent and are on their own evolutionary path," says Mark Statham. (Credit: peggycadigan/Flickr) DAD GENES SHOW RED FOX’S PATH TO NORTH AMERICA UNIVERSITY OF CALIFORNIA, DAVISrightOriginal Study Posted by Kat Kerlin-UC Davis on October 8, 2014 Scientists have investigated the paternal side of the red fox genome and discovered surprises about their origins, journey, and evolution. The researchers looked at ancestry across the red fox genome, including the Y chromosome, with data compiled for over 1,000 individuals from all other the world. Red foxes are the world’s most widely distributed land carnivore. “If you’re only looking at what your mother’s mother’s mother did, you’re only getting a small portion of the story.”“The genome and the information it contains about our ancestry and evolution is huge,” says lead author Mark Statham, an assistant project scientist with the Veterinary Genetics Laboratory of the University of California, Davis. Conventional thinking based on maternal genetics suggested that red foxes of Eurasia and North America composed a single interconnected population across the Bering land bridge between Asia and Alaska. In contrast, this new research shows that the red foxes of North America and Eurasia have been almost entirely reproductively isolated from one another for roughly 400,000 years. During this time, the North American red fox evolved into a new species distinct from its Old World ancestors. A single female line transferred from Asia to Alaska about 50,000 years ago, which distorted the previous view based on the maternal picture. AROUND THE WORLD The new genetic research, published in Molecular Ecology, further suggests that the first red foxes originated in the Middle East before beginning their journey of colonization across Eurasia to Siberia, across the Bering Strait, and into North America, where they eventually founded the North American population. “That small group that got across the Bering Strait went on to colonize a whole continent and are on their own evolutionary path,” Statham says. During the red foxes’ journey over millennia, ice sheet formation and fluctuating temperatures and sea levels offered periods of isolation and reconnection, impacting their global distribution. Statham says understanding the evolutionary history of the red fox can provide insight into how other species may have responded to climate change and those same environmental shifts. The research effort, headed by Statham and Ben Sacks, associate adjunct professor and director of the UC Davis Mammalian Ecology and Conservation Unit, involved scientists from around the world and relied heavily on specimens in natural history museums. The study received primary funding from the Systematic Research Fund through the Systematics Association of the Linnean Society of London and the Veterinary Genetics Laboratory at UC Davis. Source: UC Davis