<![CDATA[To reach the Americas the first Ice Age people had to cross an ancient land bridge between Siberia and Alaska, and then, conventional wisdom says; they waited for an ice-free corridor, believed to have been around 1,500 kilometers long, that was revealed when two ice sheets covering Canada receded, enabling them to travel south. This established theory has now been challenged by a new study which shows that this entry route would have been “biologically unviable” In the new study, an international research team used ancient DNA that had been extracted from a critical pinch-point along this corridor to explore the evolution of its ecosystem during the retreat of the glaciers. What they have created is a comprehensive picture which shows when and how different fauna and flora emerged and when the ice-covered landscape became passable. The first time a project involving prehistoric reconstruction like this has ever been completed. The researchers were able to conclude that although people may have, in fact, travelled along this corridor approximately 12,600 years ago it would have been impossible any earlier than that because the passageway would have lacked the resources critical for successful travel: like wood for fire and tools, and animals essential to the lifestyle of hunter-gatherers. If true, it means the first Americans who lived south of the ice sheets before 12,600 years ago had to have used another route. The authors suggest in their study that they likely migrated along the Pacific coast. Exactly who these people were is widely debated. Archaeologists do agree, however, that the early inhabitants of North America, including the alleged "Clovis" culture, initially appear in the archaeological record more than 13,000 years ago, when this new study suggests the ice-free corridor wouldn’t have been passable. Eske Willerslev, with the Centre for GeoGenetics, University of Copenhagen and University of Cambridge and the leader of the research, told the journal Nature, "The bottom line is that even though the physical corridor was open by 13,000 years ago, it was several hundred years before it was possible to use it. That means that the first people entering what is now the US, Central and South America must have taken a different route. Whether you believe these people were Clovis, or someone else, they simply could not have come through the corridor, as long claimed." "What nobody has looked at is when the corridor became biologically viable," Willerslev is quoted as saying, "When could they actually have survived the long and difficult journey through it?" The research team collected evidence concerning a bottleneck in the corridor, one of the last sections to become ice free. They focused on a wealth of different evidence, including pollen, macrofossils, radiocarbon dates, and DNA retrieved from sediment cores, which they acquired standing on top of a frozen lake during the winter. The group then applied a technique referred to as "shotgun sequencing" to the DNA. This approach let the team see, with amazing precision, how the bottleneck's ecosystem actually developed. Most importantly, it showed that prior to around 12,600 years ago there were no animals or plants in the corridor, so any humans traveling through it would not have been able to survive. Image courtesy of Mikkel Winther Pedersen]]>
New Study Shows How America’s Earliest People Didn’t Get There
