Team studies whether Americans were descendants of original modern humans

April 19, 2016, University of Kansas

New analyses indicate that early migrants to the Western Hemisphere were descendants of the modern humans who originated in Africa and were part of the global dispersal of modern humans around the world, according to an analysis that includes a University of Kansas anthropological geneticist.

"We have always assumed that the initial peopling of the Western Hemisphere was a single, unique and independent event," said Dennis O'Rourke, a KU Distinguished Foundation Professor in Anthropology. "By seeing it as part of a larger global process, everything we learn about other dispersals into geographic areas out of Africa within the last 50,000 years or so are relevant to our understanding of the American case."

O'Rourke is a co-author of the article "Beringia and the Global Dispersal of Modern Humans," published in the April issue of the journal Evolutionary Anthropology. The authors examined recent developments in anthropological genetics, archaeology and paleoecology and how these findings inform us about the original migration to the Americas, as well as the human occupation of the former land bridge between Alaska and Siberia, known as "Beringia."

Until recently, settlement of the Americas seemed to be largely separate from the out-of-Africa dispersal of that began at least 50,000 years ago. The earliest Americans were thought to descend from a small subset of Eurasians that migrated to the Western Hemisphere less than 15,000 years ago, O'Rourke said.

However, archaeological discoveries since 2000 have shown that Homo sapiens occupied Beringia prior to 30,000 years ago and during what is known as the Last Glacial Maximum, or LGM, he said, which is the last period in Earth's climate history when ice sheets were at their greatest extension.

"Linking the process of peopling near the time of the LGM brings the idea of 'refugia,' which we see for populations elsewhere at this time, into sharper focus as a possible mechanism for source populations in the Americas and the role that may play in structuring the genetic variation we see early in the record," O'Rourke said.

A 2007 model, known as the "Beringian Standstill Hypothesis," is based on analysis of mitochondrial DNA in samples taken from living Native American and Siberian people. The model suggests the isolated occupants of Beringia migrated at the end of the LGM to avoid inundation of the region as sea levels started to rise.

O'Rourke said the article points out many questions remain unanswered about the complicated movement of people and their genes into and out of Beringia. He said it would be key for researchers in the future to seek to obtain high-quality ancient DNA data from northeast Siberia from 15,000 to 30,000 years ago.

"Augmenting the paleoecological record across the Bering Sea basin, and expanding the archaeological record around the western and southwestern coasts of Alaska, would be quite useful," he said.

O'Rourke; Jennifer Raff, KU assistant professor of anthropology, and, postdoctoral researcher Justin Tackney were part of one such recent study. They co-authored a 2015 PNAS study that examined DNA of an infant and preterm fetus buried together in Central Alaska roughly 11,500 years ago. The analysis provided a clearer picture of the genetic diversity likely present in early Beringian populations.

In addition to DNA samples and new archaeological data, simulations and modeling of alternative demographic scenarios for how early migrants entered the Western hemisphere would also be helpful in testing alternative hypotheses to the standstill model, O'Rourke said.

As a KU alumnus, O'Rourke returned to the university in January from the University of Utah. He is considered one of the foremost experts in the United States for the use of ancient DNA to reconstruct human settlement to the Americas.

He is overseeing creation of a new state-of-the-art ancient DNA facility that will permit KU researchers to continue examining questions about ancient migrations in a variety of ways.

"Not only will we be able to analyze ancient human DNA as samples become available for study, but we are already using proxy organisms—from human prey species to human pathogens—to gain broader insights into the nature of human movement, behavior and adaptations in these early populations," O'Rourke said.

He said the KU research team believes the design of the new lab will afford the opportunity for higher throughput and allow more rapid progress in investigating patterns of genetic variation of the past.

Explore further: Ancient babies boost Bering land bridge layover: DNA links many Native Americans to infants in Alaskan grave

More information: John F. Hoffecker et al. Beringia and the global dispersal of modern humans, Evolutionary Anthropology: Issues, News, and Reviews (2016). DOI: 10.1002/evan.21478

Related Stories

Recommended for you

Sensual fresco discovered in ancient Pompeii bedroom

November 19, 2018

Archaeologists have found a fresco in an ancient Pompeii bedroom that depicts a sensual scene of the Roman god Jupiter, disguised as a swan, and a legendary queen of Sparta from Greek mythology.

Excavators find tombs buried in Bolivia 500 years ago

November 17, 2018

Archaeologists say they found tombs at a Bolivian quarry containing remains from more than 500 years ago that give an insight into the interaction of various peoples with the expanding Inca empire.

4 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

torbjorn_b_g_larsson
5 / 5 (2) Apr 19, 2016
The abstract is clearer:

"The model suggests a parallel between ancestral Native Americans and modern human populations that retreated to refugia in other parts of the world during the arid LGM. It is supported by evidence of comparatively mild climates and rich biota in south-central Beringia at this time (30,000-15,000 years ago). These and other developments suggest that the settlement of the Americas may be integrated with the global dispersal of modern humans."
Osiris1
3 / 5 (2) Apr 20, 2016
They moved because they had to. Same as other migrations. Biological law of inertia.
ricknkenosha
not rated yet Apr 30, 2016
I have yet to see anyone prove what i know of Genesis to be untrue. That carbon-14 takes a 20,000 year chunk out of actual history. And that after 1513bc a comet-encountered disaster resulted in loss of records so that each nation recalculated their genesis based on a fulcrum date. For example Egypt and Assyria and Mayans use the fulcrum date of the global Flood 2370bc. Where sothic 180 leap days is 720 years from 3090bc to 2370bc to 1650bc. And Assyria uses the 180-day drift of Venus where 584-day Venus pentacle drifts 180 in 720 years, but the real Venus drifts 180 in 600 years thus on the fulcrum changes history to 2970bc to 2370bc to 1770bc. Then the Maya use the 180 solar days of 744 years on that fulcrum as 3114bc to 2370bc to 1626bc. So already in three cases a Flood existed based on astronomy and three nations having an exact date. NEXT we have China using 720 on the fulcrum date of 2233bc, and NeoBabylon using 740 on the fulcrum date 2207bc, and the Hindu using 1200 on 1901bc.
ricknkenosha
not rated yet Apr 30, 2016
Next we have longevity based on Mars calendars. A 780-day Mars being 6 orbits in 13 years of 360-day, recognized as quarter-seasonal in 52 years (51.25 Julian) so that four seasons of 208 years in 360-day is the 205-year Mars or Marduk of Abram's father Terah. Compare Genesis to Jasher to Mayans and Ussher and we have a debate of 39-year Mars from 2126bc for Terah to 2088bc debating whether this is Terah's birth or Haran's birth and the solution is found in 2049bc as the city Harran Syria foundation mistaken as the birth of its founder Haran. Compare exact calendar cycles of Jupiter as Marduk or Mars as Marduk and it creates the same pattern cycle that would make Harran the Chinese Hawang Di of 60-year Jupiter (60 of 360-day in 59 Julian years). Way too much detail for today's EVER-CHANGING history of science-schools to convince me THEY have the correct timeline schematic. The temples of Copan prove a Sothic 1313bc July 1 new year foundation; temples in Izapa prove a 1275bc foundation

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.