For more than 100 years now, anthropologists have been debating the issue of when Southeast Asia first became populated. Famed for its genetic diversity, this part of the world is known to have been first inhabited by hunter-gatherer tribes called the Hòabìnhian, which settled in the area some 44,000 years ago.
Some scientists believe that the Hòabìnhian unlocked the secrets of agriculture without any outside help and simply became an agricultural population on their own, without any influence from the farming communities in East Asia.
Other disagree, arguing that these indigenous tribes were actually replaced by rice farmers, who migrated from the region that is now China and went on to provide the genetic ancestry for the modern-day people of Southeast Asia.
But a new study published on Friday in the journal Science debunks both theories, showing that Southeast Asians actually descend from four ancient populations.
According to Science Daily, the research was a massive undertaking that went on for two and a half years. Conducted by scientists from all over the world — the journal lists 66 authors from universities in Europe, Asia, Japan, and the United States — the study tracked down and analyzed 26 ancient DNA samples, comparing them with modern specimens from people living in Southeast Asia today.
“Our research spanned from the Hòabìnhian to the Iron Age and found that present-day Southeast Asian populations derive ancestry from at least four ancient populations. This is a far more complex model than previously thought,” said Dr. Fernando Racimo, a geneticist at the University of Copenhagen’s Natural History Museum and one of the study’s lead authors.
The 26 ancient human genomes come from various areas of Southeast Asia and were recovered from Malaysia, Thailand, the Philippines, Vietnam, Indonesia, and Laos, as well as Japan.
Unlike previous DNA sequencing studies conducted in the area, which analyzed human fossils that only went back in time to 4,000 years ago, this new research managed to come by DNA samples that were twice as old.
Some of the skeletons investigated by the researchers are 8,000-years-old and the genetic material also included DNA samples from Hòabìnhian hunter-gatherers.
Another amazing breakthrough was that the team succeeded in locating human remains belonging to a Jōmon — ancient people living in the Japanese archipelago Jōmon period between 4,000 and 300 BCE.
This was “a scientific first,” notes Science Daily, and provided the long-awaited proof that the Hòabìnhian were genetically linked with the Jōmon people.
Hugh McColl, another lead author of the new research and a colleague of Racimo’s at the Danish museum, chimed in on the results of the elaborate DNA analysis.
“Both Hòabìnhian hunter-gatherers and East Asian farmers contributed to current Southeast Asian diversity, with further migrations affecting islands in South East Asia and Vietnam. Our results help resolve one of the long-standing controversies in Southeast Asian prehistory.”
As one might expect when dealing with ancient DNA samples from tropical regions, perhaps the greatest hurdle that the researchers had to face was the hot and humid climate in which the fossils were found. As the Inquisitr previously reported, such weather conditions make DNA preservation incredibly difficult — requiring a maximum of skill from geneticists trying to extract DNA samples from old bones.
Study lead author Eske Willerslev, who is affiliated with both the University of Copenhagen in Denmark and the University of Cambridge in the U.K., commented on the laborious work and qualified the results as “astonishing.”
“We put a huge amount of effort into retrieving ancient DNA from tropical Southeast Asia that could shed new light on this area of rich human genetics. The fact that we were able to obtain 26 human genomes and shed light on the incredible genetic richness of the groups in the region today is astonishing.”