UNIVEN-led study sheds light on prehistoric migration events
How did the first humans arrive in America?
Originally, all modern humans came from Africa. About 60,000 years ago small groups of hunter-gatherers left Africa on foot and made their way into Eurasia where they settled. These were the world’s first human immigrants. Astonishingly, by the end of the ice age some 50,000 years later, modern humans had already reached the American continent which, if travelling over land, is almost as far away from Africa as it is possible to get.
These ancient human migrations took place during the last glacial period, or ice age, which lasted from 115,000 to 11,700 years ago. At that time, most of northern Eurasia, also known as Siberia, would have been a frozen wasteland, and presumably inhospitable to long-term human settlement. So how then, did humans manage to migrate across this vast region and find their way to North America? This is one of the most important, and as yet unanswered, questions in human prehistory, because it would explain how humans were able to colonise the whole world from an African origin, in such a short space of time.
Professor Yoshan Moodley from the University of Venda (UNIVEN)’s Department of Zoology has led an international team of researchers from Italy, Russia, Mexico, Germany and the United Kingdom to find an answer to this question. The team took the unusual approach of using the DNA of a human stomach bacterium named Helicobacter pylori as a biomarker for ancient human migrations. They successfully collected, sequenced and analysed bacterial strains from indigenous people across Siberia and the Americas. The bacterial DNA database they generated suggested that, remarkably, some groups of humans, known as ancient northern Eurasians, did manage to reside in Siberia throughout the bitter ice age. Yet, other human groups who originally inhabited warmer latitudes in Asia, colonised Siberia after the end of the ice age, leading to the complex mix of human populations we see in that region today.
The team also used their bacterial data set to model human migration into the Americas. It is important to remember that during the ice age, much more water was frozen at the earth’s poles, making the sea level at that time over 100 metres lower than the present-day sea level, thus exposing a land bridge between Eurasia and North America and allowing human migration. Moodley and his team showed that one small group of ancient northern Eurasians managed to successfully cross this land bridge about 12,000 years ago, and this population subsequently expanded to give rise to the indigenous Americans we see today.
This important UNIVEN-led study entitled ‘Helicobacter pylori’s historical journey through Siberia and the Americas’will be published on Monday, 14 June 2021 in the prestigious international journal Proceedings of the National Academy of Sciences of the USA (PNAS) and it is freely available for you to read or download at the journal website.
UNIVEN management congratulates Professor Moodley and his international team on this ground-breaking achievement.
For more information or to arrange an interview please contact Prof. Yoshan Moodley on 015 962 8453 / 078 586 5739 or email to yoshan.moodley@univen.ac.za
Today, the land bridge used by the first American immigrants lies over 100 metres under the Bering Sea. However, during the last ice age, low sea levels exposed the land bridge, allowing humans to walk from Eurasia into North America and populate the New World.
Picture credit: GretarssonBase map © OpenStreetMap contributors, CC BY-SA 2.0 <https://creativecommons.org/licenses/by-sa/2.0>, via Wikimedia Commons
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Director, Marketing, Branding and Communication
University of Venda
Tel: 015 062 8112/8525 or 082 745 3090
E-mail: Takalani.dzaga@univen.ac.za
