Smithsonian.com

Photo: eaghra

Oh, give me a home where the Cow-Buffalo roam – or so the unofficial anthem of the American West should go. Though plains bison are icons of America’s tough cowboy culture and rugged West, new research findings show that most of the mighty buffalo have common cow ancestors from the 1800s. In addition to being a psychological buzz-kill, the scientists warn that the muddled cow genes may have unwanted effects on how well the modern bison fare in challenging environments.

Plains bison once numbered in the tens of millions, but the species nearly went extinct in the 1880s because of overhunting. Luckily, small populations of the animals survived in Yellowstone National Park, along with 5 other herds kept by private ranchers. All in all, scientists think only about 100 surviving bison are responsible for all of the Bison alive today.

In order to bring the species back from the edge of obliteration and also as an attempt to introduce hardy bison traits into beef-producing animals, some of the ranchers who owned the private herds crossed the animals with domestic cattle. Though their efforts never took off in the beef industry, the genetic legacy of this failed experiment reverberates in bison genes today.

The researchers recorded size measurements for over 900 bison from two different environments, a harsh one on Santa Catalina Island, California, and a more friendly, food-plentiful one on a ranch in Montana. Using molecular technologies, the scientists discovered that  a small amount of cattle genetic contamination lingers in most of North America’s bison herds. Comparing the two sample populations, their results revealed that buffalo with a particular genetic trait from domestic cattle were smaller and lighter than the true-blue bison and occurred in both the harsh and friendly environments. They suspect that the smaller, leaner cattle-descended bison may not be as fit to survive in harsh environments as their purebred relatives, especially in light of increasingly extreme temperatures.

“Looking at the long-term recovery of the bison it is important to find out if this small amount of cattle genetics in an otherwise normal bison can really have a biological effect,” the researchers remarked in a prepared statement. ”Long term management efforts with bison, and possibly other species with a history of hybridization, must carefully consider the importance of genome integrity in order to preserve what is the foundation and essence of these species, their genomes.”

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