‘Phenomenal’ Ancient DNA Dataset Provides Clues to Origin of Agriculture and Ancient Languages ​​| Science

Few places have shaped the history of Eurasia as much as the ancient Near East. Agriculture and some of the world’s earliest civilizations were born here, and the area was home to the ancient Greeks, Troy and large swathes of the Roman Empire. “It’s absolutely central, and many of us work there precisely for that reason,” says archaeologist from the German Archaeological Institute Svend Hansen. “It has always been a bridge between cultures and a key driver of innovation and change.”

But one of the most powerful tools for unraveling the past, ancient DNA, has little to say about this melting pot of history and culture, in part because DNA degrades rapidly in hot climates.

Today, in three articles in this issue, researchers present the DNA of more than 700 individuals who lived and died in the region for more than 10,000 years. Together, the studies examine the history of the Near East through a genetic lens, exploring the ancestry of people who first domesticated plants and animals, settled in villages, spread precursors to modern languages and populated the epics of Homer.

The huge dataset includes DNA from burials stretching from Croatia to modern-day Iran, in an area the authors call the Southern Arc. “The sample size is phenomenal and fascinating,” says Wolfgang Haak, a geneticist at the Max Planck Institute for Evolutionary Anthropology, who was not part of the team. “The beauty of it all is bringing it all together in a larger narrative.”

This story is not just a story. The geneticists, led by David Reich and Iosif Lazaridis of Harvard University, worked with archaeologists and linguists, collecting thousands of skeletal samples and extracting and analyzing DNA, mostly from dense petrous bone from the ear, for almost 4 years. They applied better extraction methods and compared new samples with existing data, allowing them to identify even short pieces of DNA.

Their genetic history begins with the earliest days of agriculture, a period known as the Neolithic. Agriculture began in Anatolia in what is now Turkey. But DNA shows that the people who experimented with planting wheat and domesticating sheep and goats around 10,000 years ago were not simply descendants of ancient hunter-gatherers living in the region. Dozens of newly sequenced genomes suggest that Anatolia absorbed at least two separate migrations around 10,000 to 6,500 years ago. One came from today’s Iraq and Syria and the other from the eastern Mediterranean coast. In Anatolia, they mixed with each other and with the descendants of ancient hunter-gatherers. Around 6,500 years ago, the populations had merged into a distinct genetic signature.

Another genetic contribution came from the east around 6500 years ago, when hunter-gatherers from the Caucasus entered the region. Then, around 5,000 years ago, a fourth group – the steppe nomads north of the Black Sea, known as the Yamnaya – arrived, adding to the genetic picture but not fundamentally reshaping it. “The inhabitants of the Southern Arc come mainly from the Levantine, Anatolian and Caucasian components,” says Lazaridis. “The Yamnaya are like a layer of sauce, added after 3000 BCE”

Excavated near Pylos, Greece in 2015, a 3,500-year-old skeleton dubbed the Griffin Warrior has helped researchers better understand the roots of Mycenaean society.Jack Davis

This scenario confirms existing evidence that agriculture grew out of a network of people interacting and migrating in this region, others say. “It corresponds very well to the archaeological data,” explains Barbara Horejs, scientific director of the Austrian Archaeological Institute, who was not part of the team.

But other researchers question the team’s conclusion about the origins of a different cultural shift, the spread of Indo-European languages. Almost all the languages ​​spoken in Europe today come from a common root, shared with Indian languages. Scholars have traced it for years to the Yamnaya Bronze Age, which straddled both east and west of the steppes. But the authors of the new papers argue that the Black Sea steppe was not the cradle of Indo-European, but rather a stage along a journey that began earlier and further south, perhaps -being around modern Armenia.

Due to the similarities between Indo-European and Anatolian languages ​​such as Ancient Hittite, linguists had guessed that the Yamnaya left both genes and a language in Anatolia, as well as in Europe. But the new analysis finds no Yamnaya ancestry among ancient Anatolians. The team suggests that they and the Yamnaya instead share common ancestry in a hunter-gatherer population in the highlands east of Anatolia, including the Caucasus Mountains. According to them, this region is the place most likely to have spoken an Anatolian-Indo-European root language, perhaps between 5000 and 7000 years ago. “This Caucasian component is a unifying type of ancestry that we find in all places where ancient Indo-European languages ​​are spoken,” says Lazaridis, who is the first author of all three papers.

However, Guus Kroonen, a linguist at Leiden University, says this contradicts the linguistic data. The early peoples of the Caucasus would have been familiar with agriculture, he says, but the deeper layers of Indo-European have only one word for grain and no word for legumes or plough. These speakers “didn’t know agriculture very well,” he says. “The linguistic evidence and the DNA evidence don’t seem to match.”

Lazaridis says it is possible that the root language “was originally a language of hunter-gatherers” and therefore lacked terms for agriculture. The team agrees that more evidence of “proto-Indo-Anatolian” is needed, but says the Caucasus is a promising place to look.

Throughout, the articles address some criticisms of previous work on ancient DNA. Some archaeologists have complained that previous research attributed almost everything – status, identity, changes in power – to migration impulses recorded in DNA. But the new articles acknowledge, for example, that some migrations in Anatolia may not have been relevant or even noticeable to those living at the time. “It’s a response to criticism coming from the archaeological literature,” says David Anthony, archaeologist emeritus from Hartwick College, who is not a co-author but has worked with the team. “It’s really healthy.”

In another example, Yamnaya was buried in elite graves after moving to the region in northern Greece, suggesting a link between ancestry and social status. But during the later Mycenaean period in Greece – the time when Homer mythologized – the new data suggests that Yamnaya’s descendants had little impact on Greek social structure.

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The beauty of it all is bringing it all together in a bigger narrative.

  • Wolfgang Haak
  • Max Planck Institute for Evolutionary Anthropology

The evidence comes in part from the spectacular Mycenaean burial of the Griffin Warrior, a man who died in 1450 BCE near Pylos, Greece. He bore no trace of Steppe ancestry, although dozens of elite and humbler graves in Greece do. University of Cincinnati archaeologist Shari Stocker, who helped excavate the tomb in 2015 and collaborated on the new studies, says the lack of correlation between social status and steppe ancestry is not a surprise – and a healthy dose of nuance from the geneticists.

The articles also acknowledge the nuances of identity in later periods, for example in Imperial Rome. Earlier genetic studies had shown that as the empire merged, the ancestry of people in and around the city of Rome changed, with most having roots not in Europe, but further east.

After obtaining dozens of additional genomes from the Roman era in the region, the team focused on the source of these new arrivals: Anatolia. But researchers agree that people with “Anatolian” DNA moving to the Italian peninsula likely considered themselves citizens or slaves of Rome, rather than part of a separate “Anatolian” ethnic group. Contemporary chroniclers noticed the new faces in Rome and referred to many of them as “Greeks,” possibly because the peoples of the East had been speaking Greek for centuries, Lazaridis says.

Some archaeologists still believe that diaries claim too much influence for ancestry. “DNA can tell us nothing about how people shape their life world, what their social status was,” says archaeologist Joseph Maran from the University of Heidelberg. He says terms like “Yamnaya ancestry” suggest that the Yamnaya spread by moving directly from place to place, rather than through a complex intermingling of their descendants with local populations over centuries or more. “Associating history with ‘mobility’ and ‘migration’ is… outdated. »

And while the studies are a big step forward, spanning 10,000 years with 700 samples, they leave many questions unanswered, with large expanses of time and space represented by a handful of samples.

Nevertheless, several archaeologists, including Horejs, believe this injection of DNA data will shape future research. “It is our task now, and our obligation as archaeologists, to use this new data to rethink archaeological models,” she says.

About Norma Wade

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