Evolutionary analysis applied to North American and Siberian languages suggests that while most of the Beringia people migrated into North America, some migrated back to central Asia.
This polar projection map of Asia and North America shows the approximate terminal Pleistocene shoreline: the center of geographic distribution of Yeniseian and Na-Dene language is in Beringia; from this center burgundy arrows extend toward the North American coast and into Siberia; a blue arrow indicates Interior dispersals of Na-Dene. Image credit: Mark Sicoli / Gary Holton.
Previous studies have identified common language elements in the North American Na-Dene languages and the Yeniseian languages of Central Siberia.
To investigate this further, two linguists from Georgetown University and the University of Alaska Fairbanks used a technique originally developed to investigate evolutionary relationships between biological species called phylogenetic analysis.
The scientists, Dr Mark Sicoli and Dr Gary Holton, used linguistic phylogeny to work out how about 40 languages from the area diffused across North America and Asia.
They first coded a linguistic dataset from the languages, modeled the relationship between the data, and then modeled it against migration patterns from Asia to North America, or out-of-Beringia.
The findings show an early dispersal of Na-Dene along the North American coast with a Yeniseian back migration through Siberia and a later dispersal of North American interior Na-Dene languages.
“We used computational phylogenetic methods to impose constraints on possible family tree relationships modeling both an out-of-Beringia hypothesis and an out-of-Asia hypothesis and tested these against the linguistic data,” explained Dr Sicoli, who is the lead author of a paper published in the open-access journal PLoS ONE.
“We found substantial support for the out-of-Beringia dispersal adding to a growing body of evidence for an ancestral population in Beringia before the land bridge was inundated by rising sea levels at the end of the last Ice Age.”
Although the scientists cannot conclusively determine the migration pattern just from these results, and state that the study does not necessarily contradict the popular tale of hunters entering the New World through Beringia, it at the very least indicates that migration may not have been a one-way trip.
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Sicoli MA, Holton G. 2014. Linguistic Phylogenies Support Back-Migration from Beringia to Asia. PLoS ONE 9 (3): e91722; doi: 10.1371/journal.pone.0091722
