Ancient DNA shows Stone Age Europeans voyaged by sea to Africa

Stone Age people might have crossed the Mediterranean on wooden canoes, navigating from island to island by sight.Credit: Sheila Terry/Science Photo Library

Thousands of years before Odysseus crossed the ‘wine-dark sea’ in Homer’s epic poem The Odyssey, hunter-gatherers might have island-hopped their way to Africa across the Mediterranean.

The first genomic study of ancient people from the eastern Maghreb region — present-day Tunisia and northeastern Algeria — shows that Stone Age populations who lived there more than 8,000 years ago were descended, in part, from European hunter-gatherers.

The discovery, reported on 12 March in Nature1, is the first direct evidence of trans-Mediterranean sea voyaging during this time, although archaeological finds have hinted at cultural exchange between European and North African hunter-gatherers.

Using ancient genomes, researchers have mapped the emergence of agriculture in the Middle East 12,000 years ago and its spread to Europe, but the southern Mediterranean has been largely neglected.

“There’s not been much of a North African story,” says David Reich, a population geneticist at Harvard Medical School in Boston, Massachusetts, who co-led the study. “It was a huge hole.”

Working with researchers in Algeria and Tunisia, as well as Europe, Reich’s team sequenced DNA from the bones or teeth of 9 individuals from eastern Maghreb archaeological sites, who lived between 6,000 and more than 10,000 years ago.

All carried local hunter-gatherer ancestry, similar to that of ancient people from what is now Morocco, identified in earlier studies. But unlike those western Maghreb hunter-gatherers — whose ancestry was largely replaced by European farmers probably arriving through the Strait of Gibraltar — local ancestry persisted in Tunisia and Algeria long after the arrival of farmers from Europe and the Middle East.

This fits with evidence that people in the eastern Maghreb continued to hunt local animals such as land snails and forage wild plants, even while farming imported sheep, goats and cattle. Agriculture didn’t take off in the region until much later. Maybe, says Reich, the resilience of local ancestry is related to resistance to farming practices.

The genome of a man from a Tunisian site called Djebba held a major surprise: about 6% of his DNA could be traced back to European hunter-gatherers. The researchers estimate that his Maghrebi ancestors mixed with European hunter-gatherers around 8,500 years ago. There are weaker signs of these encounters in a woman from the site.

Nature Limited