New Ideas About Human Migration From Asia To Americas
Questions about human migration from Asia to the Americas have perplexed anthropologists for decades, but as scenarios about the peopling of the New World come and go, the big questions have remained. Do the ancestors of Native Americans derive from only a small number of “founders” who trekked to the Americas via the Bering land bridge? How did their migration to the New World proceed? What, if anything, did the climate have to do with their migration? And what took them so long?
A team of 21 researchers, led by Ripan Malhi, a geneticist in the department of anthropology at the University of Illinois, has a new set of ideas. One is a striking hypothesis that seems to map the peopling process during the pioneering phase and well beyond, and at the same time show that there was much more genetic diversity in the founder population than was previously thought.
“Our phylogeographic analysis of a new mitochondrial genome dataset allows us to draw several conclusions,” the authors wrote.
“First, before spreading across the Americas, the ancestral population paused in Beringia long enough for specific mutations to accumulate that separate the New World founder lineages from their Asian sister-clades.” (A clade is a group of mitochondrial DNAs (mtDNAs ) that share a recent common ancestor, Malhi said. Sister-clades would include two groups of mtDNAs that each share a recent common ancestor and the common ancestor for each clade is closely related.)
Or, to express this first conclusion another way, the ancestors of Native Americans who first left Siberia for greener pastures perhaps as much as 30,000 years ago, came to a standstill on Beringia – a landmass that existed during the last glacial maximum that extended from Northeastern Siberia to Western Alaska, including the Bering land bridge – and they were isolated there long enough – as much as 15,000 years – to maturate and differentiate themselves genetically from their Asian sisters.
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Vernon Clayson - 11/2/2007
Who decided that the migration was from Siberia to the land mass that became North America,perhaps the migration was the other way. Explorers from North America may have followed the sun towards Siberia, thinking perhaps that opportunity lay there where the sun set. North America couldn't have been too inviting for early people. The peoples of South America didn't make much of an effort to spread north, or did they, and then those in the north retreated to Siberia to escape the hordes from the south.
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