Geneticists have found thanks to DNA studies that all humans can trace back their origins to a massive expansion that started in Africa.
Four separate studies published Wednesday in the academic journal Nature suggest that all humans can trace their roots back to a massive migration that occurred in the continent over 50,000 years ago. The evolution of the homo sapiens and the start-up of modern society has been studied by the science world for decades, becoming one of the most important subjects when it comes to knowing ourselves as a species.
But there’s one question that has puzzled scientists through all of this years, how did our ancestors manage to populate the whole world? A lot of theories implicated that different types of migrations separate them, and eventually they became isolated around the globe.
However, a new set of studies has analyzed DNA traces of human ancestors in Africa determining that the human kind reached all corners of Earth after a huge migration that happened in the continent around 50,000 t0 80,000 years ago and eventually led to humans in Australia, Eurasia, and the Americas.
Geneticists studied human genes from different continents as a method to trace back in history our origins thanks to mapping genomes. The reasons for the massive migration, although it remains as an on-going debate, could be due to environmental circumstances but what scientists do know is that this was the moment when humans started creating societies around the world.
Understanding the globe’s population
Four studies aimed to understand how humans populated the world and why they left Africa in a massive expansion, although the studies had these reasons as their primary objective they considered different aspects of it.
The first study was directed by Eske Willeslev from Cambridge University and aimed to understand the beginnings of Aboriginal Australians and how they arrived at the location. Science had already informed that Australians, where one of the first and fewest civilizations that left Africa to establish in a place, where they will remain for thousands of years.
Willerslev’s study informs that Aboriginal Australians left Africa 72,000 years ago and arrived at the continent 8,000 years later to meet with the Papua New Guineans that had left Africa 58,000 years ago.
The civilization reached the location and established a society there, being one of the only societies that can be traced back to the same place they’re ancestors arrived to.
The study agrees with the three others and confirms that Papua New Guineans and Aboriginal Australians can be traced back to the same massive migration that occurred in Africa.
Willerslev’s study also confirms that this civilization separated at one point in history and began to develop different genes and characteristics from one another. Being so genetically distinct from each other just as Europans and East Asians.
“This story has been missing for a long time in science, now we know their relatives are the guys who were the first real human explorers,” said Willerslev in an interview with The Guardian.
A second study published in Nature and led by Mait Metspalu informs that when the Papua New Guinea civilization was traveling the world, they met and bred with an extinct group of Homo Sapiens that left Africa 120,000 years ago.
They found the evidence in the genes when a match between the extinct group and the Papua New Guineans occurred. According to the study, the group only met with New Guineans before becoming extinct
The studies all agree that even though a massive expansion from Africa happened, groups and civilizations were divided into substructures that found one another along the way before establishing in a continent.
These affirmations can be seen in The Simons Genome Diversity Project Study, which was the one that proved all of the human’s genes can be traced back to the massive expansion from the continent.
According to the study, people managed to create separate groups within Africa and slowly began migrating, the published data informs that the KhoeSan group separated from the Yoruba group back in Nigeria over 87,000 yeats ago. Meanwhile, the Yoruba’s separated from the Mbuti group 56,000 years ago.
“If we want to understand who we really are, we have to realize that some of the most interesting aspects of human variation are only present in under-represented small populations,” said David Reich, geneticist, and researcher from the Genome Diversity study.
Understanding climate changes at the moment
A team of Hawaiian researchers in Manoa tried to understand the climate changes that were occurring at the moment of the migration and what our ancestors were dealing with.
To understand the climate changes, researchers used a computer model that determines climate and human migration trough the years by modeling the circumstances, such as ice ages and climate changed when the spread of populations was happening over 125,000 years ago.
According to the study’s results, small waves happened with slow differences of years, the first beginning over 80,000 years ago and the last one happening 60,000 years ago. The results match the findings of the other three studies, which provides compelling evidence about how our ancestors populated our Earth.
Source: Nature