Extensive genetic study of ancient Eurasians reveals thousands of years of history
Three new scientific papers provide a fascinating and comprehensive analysis of the genomes of 777 humans who lived from the Neolithic period (around 10,000 years ago) to the Ottoman period (around 1700 CE). Overall, the research adds nuance to the story of human dispersal and connection since the dawn of civilization.
Ancient DNA for research came from sources representing a diversity of people over time. Some people were elite in their time: one sample came from the tomb of a seemingly wealthy young man who died in Minoan Crete, nicknamed the Warrior Griffon. Another came from Amesbury Archer, another wealthy man who was buried in Wessex, near Stonehenge, around 4,300 years ago. Twenty-six people buried in an Armenian necropolis during the Late Bronze Age and Early Iron were included, while many others came from farming populations in western Eurasia.
The analysis – conducted by a large interdisciplinary team of more than 200 researchers, including geneticists and genomics, archaeologists and human evolutionary biologists – clarified the migrations of some ancient human populations and how groups of people at across Eurasia interacted. Their research is published in the journal Science.
“We believe this data will be useful on its own, as it describes in detail the broad picture of the Eastern Mediterranean over time. Other researchers can use our data to infer the ancestry of migrants elsewhere,” Iosif Lazaridis, a Harvard University geneticist and lead author of the research, said in an email to Gizmodo. “The map of past migrations, both massive and isolated individuals, is getting clearer!”
The research includes three studies. The first study describes 10,000 years of genomic history in the Southern Arc, a region that can generally be described as westernmost Asia and southeastern Europe. The Southern Arc is important because it is where some of the first agricultural cultures emerged, as well as the first pottery cultures. The region (especially the fertile crescent, which is found in the Southern Arc) is often considered the “cradle of civilization”. How best to refer to the region, however, is debatable.
“The naming of the Southern Arc suggests a map projection centered on the western tip of Eurasia rather than the Anatolian Peninsula – a more intuitive geographic center of the search area,” wrote Benjamin Arbuckle and Zoe Schwandt, anthropological archaeologists at UNC-Chapel Hill. who were not affiliated with the recent works, in an accompaniment Insights Article. “Furthermore, in terms of scale, genome-based narratives often project a high-altitude view of history, mostly devoid of individuals though derived from its most personal components.”
“With this approach, history is made through vague processes of migration and admixture, but the social mechanisms remain unexplored,” Arbuckle and Schwandt added.
One of the main conclusions of the first article was that former speakers of Indo-European languages are related to the Yamnaya culture, a group of steppe herders who lived north of the Black and Caspian seas. Based on the genetic variation among the hundreds of ancient individuals whose DNA was sequenced by the team, the Yamnaya culture spread south of the Southern Arc.
“By comparing the Anatolian samples with their neighbors, we can see that the steppe influence did not reach Anatolia,” Lazaridis said. “We hypothesize that speakers of Anatolian languages (such as Hittite and Luwian) came from the east and not from the steppe; the steppe was only responsible for the Indo-European languages, that is, the linguistic ancestors of Greek, Armenian, Sanskrit, English, etc.
The second paper introduced the first sequenced ancient DNA (aDNA) from the pre-Pottery Neolithic culture in Mesopotamia (what is now southeastern Turkey and northern Iraq), Cyprus and northwestern Iran . Work has also identified at least two human scatters from the Fertile Crescent in Anatolia.
“The genetic results support the scenario of a network of pan-regional contacts between early farming communities,” said Ron Pinhasi, a biological anthropologist specializing in ancient DNA at the University of Vienna and co-author of the work, in a university Release. “They also provide new evidence that the Neolithic transition was a complex process that occurred not just in one central region, but across Anatolia and the Near East.”
The third job probed the ancestral connections of individuals from southern Europe and western Asia; some particular findings were that the Greek elites of Mycenae were genetically similar to the general population, and that there was not much admixture between the inhabitants of eastern Turkey and southern Armenia (then Urartian ) with steppe populations.
“Ancient source populations are highly differentiated from each other, and the authors find over the past 10,000 years a reduction in this differentiation as populations carrying these ancestries mix (“homogenization”),” said said Mohamed Almarri, a geneticist at England’s Sanger Institute who was not affiliated with the research, in an email to Gizmodo.
“However, this process was not uniform, and for me, this is one of the main strengths of the articles,” added Almarri. “Comparing the proportions of sources over time and space in their samples, they find differences in many places, raising questions about why these patterns evolved.”
The third work also revealed that the inhabitants of ancient Anatolia remained genetically distinct from other populations throughout the Byzantine period and represented “the demographic core of much of the Roman Empire”, as the article.
“[The researchers] have produced an astonishing dataset, unimaginable in magnitude just a decade ago,” Arbuckle and Schwandt wrote. “In the future, the growing body of ancient genomic data will continue to transform views of human history. This work can be particularly effective if scholars recognize their lack of neutrality and embrace their role in constructing narratives while allowing room for diverse perspectives that shed light on people and places whose history is less well known.
As aDNA sequencing methods improve, scientists will be able to extract more nuances from human scattering and mixing over time. Our history – where we all come from and the related question of who we are – can be stated at the base pair level.
After: Footprints suggest humans migrated deep into North America earlier than thought