DNA analysis of bison fossils suggests that humans moved to North America 13,000 years ago along the Rocky Mountains route.
For years, researchers have debated how the early humans migrated to North America. They already knew humans entered the South 15,000 years ago through a coastal Pacific path, but they were not sure about a second route along the Rocky Mountains. They always suspected that people used that path for migration too, but when and how it was used has long been uncertain.
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Now, new research suggests that the path along the Rocky Mountains was indeed used in North American migration when a lush land corridor was exposed by Canada’s melting ice sheets some 13,000 years ago.
To arrive at the latest conclusion, researches tracked the movements of Ice Age Bison who also used the corridor to migrate north. Then, bison were followed by early humans.
Previous research has shown that the bison populations residing north and south of the ice sheet were genetically different from each other by the time corridor opened. Since the southern bison were different from northern bison, researchers decided to analyze the bison fossils found within the corridor region. So, they can determine when bison from the northern and southern population began to use the path and when they met up in the middle.
Using radioncarbon dating and DNA analysis of the fossils, researchers suggested that both populations of bison overlapped in the corridor by 13,000 years ago.
“The radiocarbon dates told us how old the fossils were, but the key thing was the genetic analysis, because that told us when bison from the northern and southern populations were able to meet within the corridor.” Lead author Peter Heintzman from UC Santa Cruz said.
The research also suggests that south part of the corridor opened first and human migration was mostly from south to north.
“When the corridor opened, people were already living south of there. And because those people were because those people were bison hunters, we can assume they would have followed the bison as they moved north into the corridor.” Co researcher Beth Shapiro said.
The bison of Pleistocene epoch were bigger than the modern-day bison. Both south and north bison populations never interacted to each other due to massive ice sheets until the ice receded and a corridor opened. Bison began to move up and down the corridor after that.
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“Bison fossils are the most widespread Quaternary mammal in western North America and of interest because they survived the extinctions at the end of the Pleistocene, unlike most other North American large animals,” said coauthor Duane Froese. “We were able to sample bison fossils, largely from museum collections, including critical ones from central Alberta that dated to the initial opening of the corridor.”