Science Now Discoveries from the world of science and medicine

The DNA of ancient Canaanites lives on in modern-day Lebanese, genetic analysis shows

The Canaanites lived at the crossroads of the ancient world.

In a territory that would later be known as the Middle East, they experienced wars, conquests and occupations over thousands of years. As a result, evolutionary geneticists expected their DNA to reflect substantial mixing with incoming populations.

A new genetic analysis shows that scientists were wrong. According to a study in the American Journal of Human Genetics, today’s Lebanese share a whopping 93% of their DNA with ancient Canaanites who lived nearly 4,000 years ago.

The study also found that the Bronze Age inhabitants of Sidon, a major Canaanite city-state in modern-day Lebanon, had the same genetic profile as people who lived 300 to 800 years earlier in present-day Jordan.

Later known as Phoenicians, the Canaanites have a murky past. Nearly all of their own records have been destroyed over the centuries, so their history has been mostly pieced together from archaeological records and the writings of other ancient peoples.

Archaeologists at the Sidon excavation site have been unearthing ancient Canaanite secrets for the last 19 years in the still-inhabited Lebanese port city. They have uncovered 160 burials from the Canaanite period alone, including children buried in jars and adults placed in sand, said Claude Doumet-Serhal, director of the excavation.

Evolutionary geneticists are taking the work a step further.

Aided by new DNA sampling techniques, they sequenced the whole genomes of five individuals found in Sidon who lived about 3,700 years ago.

The team compared the genomes of these ancient Canaanites with those of 99 Lebanese people currently living in the country, as well as with previously published genetic data from modern and ancient populations across Europe and Asia.

First, they investigated the genetic ancestry of the Canaanites themselves. They found that these Bronze Age inhabitants of Sidon shared about half their DNA with local Neolithic peoples and the other half with Chalcolithic Iranians. Interestingly, this genetic profile is nearly identical to the one evolutionary geneticist Iosif Lazaridis and his team found last year in Bronze Age villagers near ‘Ain Ghazal in modern-day Jordan.

This suggests that Canaanites were spread across a wide region during the Bronze Age, from urban societies on the coast to farming societies further inland. It also supports the idea that different Levantine cultural groups — such as the Moabites, Israelites and Phoenicians — had a common genetic background, the study authors said.

By comparing the lengths of similar strands of DNA, the researchers determined that the genetic mixing of the Levantine and Iranian peoples happened between 6,600 and 3,550 years ago. If they had more ancient DNA samples from the region, they could come up with a more precise estimate, they added.

Next, the team compared the Canaanite genome with the genetic makeup of people who currently inhabit the ancient Canaanite cities. So they collected DNA from 99 modern Lebanese people — Druze, Muslim, and Christian alike.

As expected, they found some new additions to the Lebanese genome since the Bronze Age. About 7% of modern Lebanese DNA originates from eastern Steppe peoples found in what is now Russia — an ancestry not seen in the Bronze Age Canaanites or their ancestors.

But what really surprised the team was what was missing from the DNA of today’s Lebanese.

“If you look at the history of Lebanon — after the Bronze Age, especially — it had a lot of conquests,” said Marc Haber, a study leader from the Wellcome Trust Sanger Institute in Hinxton, England. He and his colleague Chris Tyler-Smith expected to see greater genetic contributions from multiple conquering peoples, and they were surprised that as much as 93% of the Lebanese genome is shared with their Canaanite predecessors.

Though a 7% genetic influx from the Steppe seems very small, that number might be covering some hidden complexities, said Lazaridis, who worked on the Bronze Age Jordanian samples but was not involved in the new study.

Not much is known about the migrations of these eastern Steppe populations, he said. If the genomes of the incoming people were only half Steppe, for example, 14% of the Lebanese genome could have come from the new migrants.

Haber and Tyler-Smith said they want to explore this complexity further.

“Who were those eastern migrants? Where did they come from? And why did they migrate toward the Levant region?” Haber said. Analyzing more samples from different locations and time periods could lead to an answer.

The team also wanted to know if the individuals from Sidon are more similar to modern-day Lebanese than to other modern Eurasian populations.

Despite small genetic variations between the three religious groups caused by preferential mating over time, the Lebanese genome is not widely varied. As a whole, the Lebanese people have more genetic overlap with the Canaanites from Sidon than do other modern Middle Eastern populations such as Jordanians, Syrians or Palestinians.

The difference is small, but it’s possible that the Lebanese population has remained more isolated over time from an influx of African DNA than other Levantine peoples, Lazaridis suggested.

The findings have powerful cultural implications, said Doumet-Serhal, who worked on the new study. In a society struggling with the ramifications of war and fiercely divided along political and sectarian lines, religious groups have often looked to an uncertain history for their identities.

“When Lebanon started in 1929,” Doumet-Serhal said, “the Christians said, ‘We are Phoenician.’ The Muslims didn’t accept that and they said, ‘No, we are Arab.’”

But this work carries a message of unity.

“We all belong to the same people,” she said. “We have always had a difficult past … but we have a shared heritage we have to preserve.”

mira.abed@latimes.com

Twitter: @mirakatherine

Copyright © 2017, Los Angeles Times
EDITION: California | U.S. & World
65°