According to a new study by scientists at Texas A&M University, all bison in North America carry multiple small, yet identifiable regions of DNA that originally came from cattle.
The research confirms there are, in fact, no purebred bison on the continent.
“I did genetic bison research 20 years ago and, at that time, it was cutting edge,” said James Derr, director of the DNA Technologies Core Laboratory at the university’s Departmentt of Veterinary Pathobiology.
“We looked for evidence of introgression of cattle genes in bison and we found it in most places such as cattle mitochondrial DNA from the mother or markers in the nuclear genome that distinguished cattle from bison.
“(Back then) we found cattle genetics in a lot of bison herds but not in those in Yellowstone, Wind Cave, Elk Island or Wood Buffalo national parks. Since then, we have gone through another generation of advancing technology. The technology today is for whole genome sequencing. That means there is no place in the genome where anything can hide. We can look at every single gene in a bison and determine whether a gene or a DNA sequence came from bison or cattle.”
When European settlers arrived in North America, an estimated 40 million bison roamed the prairies and high plains. But populations were decimated by overhunting and expansion of settlement to the point where, by the mid-1880s, their numbers were down to a perilous few hundred in just six herds. But even as those animals were under threat of extinction, efforts by conservationists and sportsmen to save the species were underway.
In 1905, the American Bison Society was formed with William Hornaday, first director of the New York Zoological Park, as president. In 1907, ABS shipped 15 bison (six bulls and nine cows) from the zoo to the Wichita Mountains Wildlife Refuge in Oklahoma. The organization continued to secure populations of bison in public herds until it was disbanded in 1935 and then relaunched in 2005 by the Wildlife Conservation Society.
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