Sunday, January 7, 2018

Sunrise Girl Casts Light on Human Conquest of Americas

Ancient DNA Reveals a Completely Unknown Population of Native Americans
Sunrise girl-child ("Xach'itee'aanenh T'eede Gaay") lived some 11,500 years ago in what is now called Alaska, and her ancient DNA reveals not only the origins of Native American society, but reminds the world of a whole population of people forgotten by history millennia ago.

It's widely thought that the first American settlers crossed over into Alaska from Siberia via the Bering Land Bridge, which once linked up Asia and North America – although scientists are ever debating how these ancient travellers made their journey.

What's less clear is who these people were, how many groups made the trip, and how they then settled the new continent under their feet. That's where sunrise girl-child comes in.

Her remains, and those of another ancient infant known as "YeƂkaanenh T'eede Gaay" (dawn twilight girl-child), were found by Potter and fellow researchers at an Interior Alaska archaeological site called Upward Sun River during excavations in 2013.

In a new study published this week, the team reports that a genetic analysis of sunrise girl-child's DNA shows she belonged to a forgotten people called the Ancient Beringians, unknown to science until now.

Before now, there were only two recognised branches of early Native Americans (referred to as Northern and Southern). But when the researchers sequenced sunrise girl-child's genome – the earliest complete genetic profile of a New World human to date – to their surprise it matched neither.

Using genetic analysis and demographic modelling, the team concludes a single founding ancestral Native American group split from East Asians around 35,000 years ago, most likely somewhere in north-east Asia. At some point, it's suspected these people moved as one in a single mass migration into North America, before – some 15,000 years or so later – the population split into two groups.
What could be so awful as to spur a mass migration across a nearly glacial, low lying tundra?
One of the groups became the Ancient Beringians – the other group were the ancestors of all other Native Americans – although it remains possible this division was already occurring before the Bering Land Bridge was crossed. "We were able to show that people probably entered Alaska before 20,000 years ago," says evolutionary geneticist Eske Willerslev from the University of Cambridge in the UK.

"It's the first time that we have had direct genomic evidence that all Native Americans can be traced back to one source population, via a single, founding migration event." Countless generations after the trek, sunrise girl-child and dawn twilight girl-child – thought to be first cousins – were born into an isolated people in the icy Alaskan wilderness of the Late Pleistocene.
This seems to settle the question of whether humans were in the New World prior to Clovis Man. They clearly were. It does not account for some of the extreme ages assigned to some pre-Clovis sites south of Alaska. I think there's still room for some "leakage" of population around the glacial barrier, possibly by skipping down the coast from safe harbor to safe harbor.

Wombat-socho has "Late Night With Rule 5 Sunday: Stacey Dash" ready for your browsing pleasure at The Other McCain.

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