A major international collaboration between researchers at the University of Huddersfield and the University of Southampton has provided new insights into when and how modern humans, Homo sapiens, first settled in New Guinea and Australia.
The project brings together experts in archaeogenetics and marine archaeology, and was funded by the European Research Council awarded to Professor Helen Farr from the University of Southampton. The genetic analysis was led by Professor Martin Richards from the University of Huddersfield.
Ancient Sahul and early human migration
During the last ice age, global sea levels were much lower than they are today. At that time, New Guinea and Australia were combined into a single land mass called Sahul. Scientists have long debated when people first reached this ancient continent and what routes they used to get there.
To address these questions, researchers combined expertise from multiple fields, including genetics, archaeology, geosciences, and oceanography. Their goal was to better understand who these early immigrants were, where they came from, and when they traveled.
Discussion of long and short chronology
It is well known that the ancestors of New Guineans and Indigenous Australians have lived in Sahul for tens of thousands of years. Many of Australia’s Aboriginal people maintain deep cultural ties to the land, reflecting this long history.
However, scientists do not always agree on the exact time of the first settlement. Two major theories exist. The “Long Chronicle” claims that humans arrived about 60,000 years ago. Competing “short chronicles” suggest a later arrival, approximately 45,000 to 50,000 years ago.
To investigate this debate, the research team analyzed human mitochondrial DNA (mtDNA), which is passed down through the maternal line. Because mtDNA accumulates changes over generations, it can be used to reconstruct detailed genealogies going back far into the past.
DNA evidence points to earlier arrival
The research team studied approximately 2,500 mtDNA genomes from Australian Aboriginals, New Guineans, and populations from Southeast Asia and the Western Pacific. By constructing genetic family trees and tracking how lineages spread between regions, they were able to estimate when different groups diverged.
Researchers used the gradual accumulation of genetic changes known as the “molecular clock” to date the oldest lineage, found only in Australian Aborigines and New Guineans, to around 60,000 years ago. This strongly supports the long-age model.
Multiple routes to Sahul
Genetic evidence also reveals where these early populations came from. The oldest lineages date back to Southeast Asia, but they do not come from a single location.
Most lineages refer to northern regions such as northern Indonesia and the Philippines. At the same time, notable parts originate from southern regions such as southern Indonesia, Malaysia, and Indochina. This pattern suggests that early humans likely entered Sahul along at least two separate migration routes, both of which occurred around the same time.
Why the findings matter
These results are important because they are in good agreement with archaeological and environmental evidence. In recent years, some genetic studies have begun to support a more recent arrival, but this new analysis strongly supports an earlier date.
Professor Richards said: “We feel this provides strong support for a long chronology. Still, estimates based on molecular clocks can always be challenged and mitochondrial DNA represents only one lineage. We currently have hundreds of We are analyzing the entire human genome sequence (3 billion bases compared to 16,000 bases each) and testing the results against thousands of other lineages across the human genome. Further archaeological analyzes will be conducted in the future.” It also holds promise that ancient DNA may be recovered from important archaeological sites, allowing us to test and differentiate these models more directly. ”
Professor Farr added: “This is a great story that helps further our understanding of human origins, maritime migration and early seafaring stories. It reflects the really deep heritage of the indigenous communities of this region and the skills and skills of the early seafarers.”
Published research and future research
The discovery will be published in a magazine scientific progresspublished by the American Association for the Advancement of Science. A related study, led by Dr. Pedro Soares from the University of Minho, tested the reliability of the molecular clock method used in the analysis. scientific report.
Taken together, these studies provide a clearer picture of one of humankind’s earliest and most remarkable migrations.
