Ancient DNA maps ‘dawn of agriculture’

A woman harvests wheat by hand in a field in Turkey

Most of Europe’s first agricultural population descended from farmers in the Anatolian Peninsula, in what is now Turkey.Source: Fatih Kurt / Anadolu Agency / Getty

Sometime 12,000 years ago, nomadic hunter-gatherers in the Middle East made one of the most important transformations in human history: they began to stay put and turned to agriculture.

A pair of ancient DNA studies1And2 – including one of the largest collections of ancient human genomes published to date – has assimilated the identity of the hunters who settled.

Archaeological and genetic evidence indicates that humans first began farming in the Middle East. This transition—which also later occurred independently in other parts of the world—is known as the Neolithic Revolution, and is associated with the first plants and domestic animals.

Previous ancient genome studies3 He alluded to the complex origins of farmers in the Middle East, including geographically distinct groups of hunters and gatherers with different genetic inheritances.

Most of Europe’s first agricultural population descended from farmers in the Anatolian Peninsula, in what is now Turkey. “What happened before they set out to migrate and spread agriculture in Anatolia and Europe?” asks Laurent Excoffier, a population geneticist at the University of Bern.

To address this question, a team led by Excoffier has sequenced the genomes of 15 hunter-gatherers and early farmers who lived in southwest Asia and Europe, along one of the major migration routes taken by early farmers to Europe – the Danube. The remains came from several archaeological sites, including some of the first agricultural villages in western Anatolia.

The researchers have produced “high coverage,” or high-quality genomes — a rarity in ancient genomics work. This allowed them to correlate the data to obtain demographic details, such as shifts in population size, which are usually outside the scope of ancient DNA studies based on less complete genomes.

mix and pray

The Excoffier team found that the farmers of ancient Anatolia descended from frequent mixing of distinct hunter-gatherer groups from Europe and the Middle East. These groups split for the first time around the height of the last Ice Age, about 25,000 years ago. Modeling suggests that western populations of hunter-gatherers nearly became extinct, before rebounding as the climate warmed.

Once established in Anatolia, the Excoffier team found that early farming groups moved west into Europe in a stone-like fashion, beginning around 8000 years ago. They occasionally mingled – but not extensively – with local fishermen. “It is the spread of people and farming communities that has pushed agriculture further west,” says Excovier. The study was published in prison cell on May 121.

The findings chime with those of an ancient genomics study published on the bioRxiv preprint server May 52. A team led by paleogeneticist Eske Willerslev of the University of Copenhagen has sequenced the genomes of 317 hunters, gatherers and early farmers from across Eurasia, the largest ancient genome study from this period. This study also found an ancient division between eastern and western hunter-gatherer groups, and traces the arrival of Anatolian farmers to Europe, some 8,700 years ago in the Balkans. Willerslev declined to comment on the study before it was published in a journal.

Studies are revealing finer details of the dawn of agriculture that was previously drawn only with broad brushstrokes and is based on small numbers of genomes with relatively low coverage, says Pontus Skoglund, a paleogeneticist at the Francis Crick Institute in London. “Both of these papers are where ancient DNA should be next.”