Scientists Track Origin of American Bison to Common Female Ancestor Who Arrived between 130,000 to 195,000 Years Ago

% of readers think this story is Fact. Add your two cents.

New research by Professor Beth Shapiro of the UC Santa Cruz Genomics Institute and University of Alberta Professor Duane Froese has identified North America’s oldest bison fossils and helped construct a bison genealogy establishing that a common maternal ancestor arrived between 130,000 and 195,000 years ago, during a previous ice age.

Shapiro, Froese and colleagues used new techniques for ancient DNA extraction and sequenced the mitochondrial genomes of more than 40 bison, including the two oldest bison fossils ever recovered. Comparing these genomes to additional Siberian and North American bison clarifies the earliest parts of the bison family tree.

Credit:  Yukon Government

“There has long been a controversy about the timing of bison arrival in North America,” said Shapiro. Bison arrival in North America marks the beginning of what geologists call the “Rancholabrean Land Mammal Age,” which is used to discriminate between different ecological periods in the continent’s history. “Until recently, the fossil records from different parts of North America disagreed with each other, with a few fossil localities suggesting that bison arrived millions of years ago, but most old fossil sites showing no evidence of bison at all,” Shapiro said. As new methods to date fossil localities emerged, the ages of the sites in North America with purportedly very old fossil bison have all been questioned, leaving the timing of bison arrival a mystery.

The paper, “Fossil and genomic evidence constrains the timing of bison arrival in North America,” was published in Proceedings of the National Academy of Sciences. http://dx.doi.org/10.1073/pnas.1601077113