12,000 Years of Genetic History Suggests Some Truth to the Proverb 'All Roads Lead to Rome'

There may be some truth to the proverb "all roads lead to Rome." Researchers have discovered a rich genetic history of the area, extending as far back as Mesolithic times some 12,000 years ago. The research has been published in the journal Science.

At the peak of the Roman Empire, the city of Rome was unparalleled—"Rome was like New York City," Guido Barbujani, a population geneticist at the University of Ferrara, Italy, who was not involved in the study, said in a related article published by Science.

Like the New York of today, Ancient Rome was a melting pot of people and cultures and is widely thought to have been the first city in the world to reach more than one million people. It is a record that was not surpassed until Europe's Industrial Revolution some 1,500 years later, the study's authors say. Meanwhile, the surrounding empire drew in 70 million inhabitants across three continents—Europe, the Near East and North Africa.

"We did not anticipate to find out that Rome was a cosmopolitan center right from the early stages—during the Iron Age," co-author Ron Pinhasi at University of Vienna told Newsweek. "We also did not expect to find immigrants from North Africa and potentially also further south, the Middle East, and Northern Europe."

But while we might know a lot about the archaeology and history of the city, relatively little is known about the genetics of its inhabitants. Hence, a new study led by researchers at institutions in the U.S. and across Europe.

roman mosaic
There may be some truth to the famous proverb “all roads lead to Rome”: recent research shows the city has been "a cosmopolitan center” since the Iron Age. Pictured: Mosaic Recovered from the Ruins of Pompeii. Frédéric Soltan/Corbis/Getty

The team examined genome data belonging to 127 individuals sourced from 29 archaeological sites in Rome and its surrounding regions from the Mesolithic period to modern times (i.e. 1800 and later). The analysis revealed three genetic "clusters," suggesting relatively little genetic change between the Iron Age and the present.

The first of these clusters was that of the three Mesolithic hunter-gatherers from a cave in the Apennine Mountains. These hunter-gatherers were between 12,000 and 9,000 years old and showed relatively little heterozygosity, the study's authors say. The analysis revealed their genetics were most similar to those of Western hunter-gatherers.

During the Neolithic period (7,000 to 6,000 BCE), there was a major ancestry shift and a second genetic cluster, triggered by the transition to farming, population growth and—crucially—genetic contribution from Anatolian and Iranian farmers.

This was followed by a second major ancestry shift during the Bronze Age (2,900 to 900 BCE) when advances in technology saw increased mobility between populations. Chariots and wagons enabled movement on land while improvements in sailing technologies made it easier to cross the Mediterranean. During this period, researchers found greater evidence of North African ancestry and Iranian Neolithic ancestry.

As Imperial Rome established itself, growing from a city-state to an empire that extended to England in the west, North Africa in the South and Assyria in the East, it drew people from southern and central Italy, Greece, Cyprus and Malta in the eastern Mediterranean. While there have been some shifts in genetics in the centuries since—particularly as the political focus of Rome shifted to west and central Europe—it has remained relatively unchanged since.

"It takes a lot of work and recourses to develop a project on this scale," said Pinhasi.

"Obviously this is just the first step and more studies are needed in order to illuminate the complex social processes in Rome and interactions between different people from different ancestries, in relation to other aspects such as social stratification. "