Genetically unique group from southern Greece can trace paternal ancestry to the Bronze Age

A group of people living on the southern tip of Greece’s Peloponnese Peninsula have been genetically isolated for more than 1,000 years and can trace their roots back to the Bronze Age, a DNA analysis has revealed.

New genetic research shows that this group, known as Deep Maniot Greeks, is paternally descended from ancient Greeks and Byzantine Romans. Long periods of genetic isolation and strictly patriarchal clans likely contributed to the unique genetics of Deep Maniot Greeks over the past 1,400 years, the study authors said.

The Mani Peninsula is the middle of three peninsulas that extend south from mainland Greece. In ancient times, this region was part of the Laconia region, which was ruled by the city-state of Sparta in the 7th century BC. With the invasion of Slavic tribes in the 6th century AD, much of the Peloponnese region of Greece experienced a dramatic demographic change. However, the Mani Peninsula was spared, and the Deepmanio people who lived at the southern tip of the peninsula were geographically and culturally isolated from the rest of Greece.

you may like

In a study published Wednesday (Feb. 4) in the journal Communications Biology, researchers analyzed the DNA of more than 100 living deep maniots and found that they are “genetic islands” due to years of isolation.

“Our results show that historical isolation has left behind distinct genetic signatures,” study lead author Leonidas Romanos Davlanoglou, a zoologist at the Natural History Museum at Oxford University, said in a statement. “Deep Maniot preserves a snapshot of the genetic landscape of southern Greece before the demographic upheaval of the early medieval period.”

During the European Migration Period (c. 300 to 700 CE), also known as the “Barbarian Invasions,” various groups of people moved across the continent, including Germanic tribes, Visigoths, Huns, and early Slavs. This resulted in numerous migration waves, only some of which are recorded historically. Ancient DNA research is beginning to unravel these migratory population waves.

However, historical, linguistic, and archaeological evidence suggests that these migratory movements did not affect the Deep Maniot. So Dabranoglou and his colleagues turned to DNA analysis of modern maniots to find out why.

The researchers examined genetic markers on the Y chromosome (passed from father to child) of 102 people with paternal Deep Maniot ancestry and mitochondrial DNA (passed from mother to child) sequence data of 50 people with maternal Deep Maniot ancestry.

DNA analysis revealed that the Deep Maniots had a very high frequency of unusual paternal lines that originated in the Caucasus region about 28,000 years ago, the researchers wrote in the study. And compared to the DNA of modern mainland Greeks, the Deep Maniot DNA lacked evidence of a common lineage that came from Germanic and Slavic peoples during the immigration period.

Taken together, these results suggest that genetic drift (reduced genetic diversity due to small population size) played an important role in shaping the deep maniot patrilineage, creating a kind of “genetic island,” the researchers wrote. The researchers noted that this paternal ancestral island has roots in the ancient Balkans and western Asia, with strong ties to the Greek-speaking peoples of the Bronze Age, Iron Age, and Roman times.

you may like

However, analysis of the maternal Deepmaniot lineage by mitochondrial DNA revealed a more complex genetic picture. The researchers identified 30 different maternal lines from a population sample of 50 deep maniots. Most of these lineages have connections to the Bronze Age and Iron Age peoples of Western Eurasia, but some appear to be unique to the Deep Maniots, and none correspond exactly to other modern European populations.

“These patterns are consistent with a strongly patriarchal society, where the male lineage remained locally rooted, while a small number of women were incorporated from outside communities,” study co-author Alexandros Heracleides, an epidemiologist at the European University of Cyprus, said in a statement.

Both paternal and maternal DNA markers show evidence of founder effects, which occur when a new population is established by a very small subset of a larger population. The new population contains only a few founder genes and, over time, becomes distinct from the larger population.

Current Deepmaniot genetics reveal that there was a founder effect among their paternal ancestors around 380 to 670 AD. As a result, more than 50% of today’s Maniot men descend from a single male ancestor from the 7th century. The researchers found that there was also a founder effect for maternal ancestors from around 540 to 866, suggesting that the numbers of maternal and paternal lines declined at about the same time.

The DNA study suggests that the Deepmaniot population “represents a snapshot of the genetic landscape of the Greek-speaking world before the demographic disruption of the immigration era,” the researchers wrote.

“Many of the oral traditions of common descent, some dating back hundreds of years, are now being verified by genetics,” study co-author and independent researcher Athanasios Kofinakos said in a statement.