High levels of human movement in parts of Western Asia – which includes the modern-day Middle East – led to a more genetically connected society well before the rise of cities, not the other way around as previously thought, new research shows.
An international team of scientists looked at DNA data from 110 skeletal remains dated 3000 to 7500 years ago gathered from archaeological sites in Anatolia (Turkey), the Northern Levant, which includes countries on the Mediterranean coast such as Israel and Jordan, and the Southern Caucasus, which includes Armenia and Azerbaijan.
Based on their analysis, they describe two genomic events that occurred around 8500 and 4000 years ago that pointed to long-term genetic mixing in the region and subtle population movements within the area, shedding light on a long-standing question.
“Within this geographic scope, you have a number of distinct populations, distinct ideological groups that are interacting quite a lot and it hasn’t really been clear to what degree people are actually moving or if this is simply just a high contact area from trade,” says Christina Warinner from Harvard University, US, a senior author of a paper in the journal Cell.
“What we can see is that rather than this period being characterised by dramatic migrations or conquest, what we see is the slow mixing of different populations, the slow mixing of ideas, and it’s percolating out of this melting pot that we see the rise of urbanism – the rise of cities.”
The study was led by the Max Planck-Harvard Research Centre for the Archaeoscience of the Ancient Mediterranean and included researchers from many disciplines and countries, including Australia, Azerbaijan, France, Italy, Germany, South Korea, Turkey, and the US.
The aim, they say, was to fill in some of the anthropological gaps between the origins of agriculture and of cities.
Western Asia is known for its early trade routes, which laid the foundation for what would become the Silk Road, but even before being connected with other regions, its populations had developed distinct traditions and systems of social organisation.
“What we see in archaeology is that the interconnectivity within Western Asia increased and areas such as Anatolia, the Northern Levant, and the Caucasus became a hub for [the] exchange of ideas and material culture,” says lead author Eirini Skourtanioti, from Germany’s Max Planck Institute.
The skeletons were housed in different museums and labs around the world. The samples for analysis were taken from their teeth and the petrous, which is part of the inner ear.
In their paper, the authors outline how approximately 8500 years ago, populations across Anatolia and the Southern Caucasus began genetically mixing, resulting in a gradual change in genetic profile that over a thousand years slowly spread across both areas and entered into what is now northern Iraq.
The other shift they detected wasn’t as gradual. Samples from the ancient cities of Alalakh and Ebla in what is now southern Turkey and northern Syria show that around 4000 years ago the Northern Levant experienced a relatively sudden introduction of new people.
The paper also presents new information about long distance migration during the late Bronze Age. The researchers determined that a lone corpse buried in a well in Hatay genetically belonged in Central Asia 4000 years ago, not at a site that is part of present-day Turkey.
“We can’t exactly know her story, but we can piece together a lot of information that suggests that either she or her ancestors were fairly recent migrants from Central Asia,” says Warinner.
“We don’t know the context in which they arrived in the Eastern Mediterranean, but this is a period of increasing connectivity in this part of the world.”
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