An international scientific team has unraveled the genetic profile of one of the most distinctive and isolated populations in Europe: the inhabitants of Deep Mani, at the southern tip of the Peloponnese peninsula in Greece. The results, published in the journal Communications Biology, map a biological landscape of unparalleled historical isolation on the continent, where paternal lineages trace uninterrupted back to Bronze Age, Iron Age, and Roman Greece, forming a unique genetic “island” on the mainland.
The research, led by the University of Oxford in collaboration with Tel Aviv University, the National and Kapodistrian University of Athens, the Areopoli Health Center, the European University of Cyprus, and FamilyTreeDNA, provides the first large-scale genomic evidence that corroborates historical and archaeological hypotheses about the exceptionalism of this region. While the rest of mainland Greece and the Balkans experienced profound demographic transformations after the fall of Rome, especially with the Slavic migrations between the 6th and 8th centuries AD, the population of Deep Mani remained remarkably impermeable to these flows.
Our results demonstrate that historical isolation left a clear and indelible genetic signature, explained the study’s lead author, Associate Researcher Dr. Leonidas-Romanos Davranoglou, of the University of Oxford, Tel Aviv University, and the University of Athens. The Maniots of Deep Mani preserve a snapshot of the genetic landscape of southern Greece prior to the demographic upheavals of the Early Middle Ages. It is very likely that they descend directly from the same communities that, more than fourteen hundred years ago, built and inhabited this rugged landscape.
The study focused on analyzing paternal lineages, through the Y chromosome, and maternal lineages, through mitochondrial DNA, of volunteers whose family origins trace back to the villages of Deep Mani. The methodology required representative sampling of different clans, given the peculiar social structure where many localities are traditionally inhabited by a single extended family. This approach was made possible through close collaboration with the community, facilitated by years of medical work and trust built by co-author Dr. Anargyros Mariolis, director of the Areopoli Health Center and himself a native of the region.
The community participated in every stage of the research, from planning the sampling strategy to interpreting the results for their fellow citizens, stated Dr. Mariolis. This study gives voice to the stories of our ancestors. As a Maniot, I wish my ancestors could witness how many of their oral traditions are now verified through genetics. It is a moment of immense pride and connection with our history.
Paternal lineages: uninterrupted continuity since Antiquity
The most revealing finding lies in the extraordinary continuity of paternal lineages. The vast majority are directly linked to local Greek-speaking groups established in the region during the Bronze Age, Iron Age, and Roman rule. This male genetic continuity is so pronounced that its geographic and temporal distribution closely reflects the placement of the emblematic fortified stone towers and the megalithic religious structures—unique in the world—that dot the landscape of Deep Mani.
The coherence between the genetic pattern and the historical settlement pattern strengthens the thesis of direct descent from Late Antiquity. Our study demonstrates how geography, social organization, and historical circumstances can preserve ancient genetic patterns in certain regions long after they have been altered elsewhere, added Dr. Davranoglou.
The analysis revealed an even more specific detail: more than 50% of present-day Maniot men descend from a single common male ancestor who lived around the 7th century AD. This extreme concentration points to a period of severe demographic crisis—a “bottleneck” in which the population was reduced to very few families—likely due to a combination of plagues, armed conflicts, and the general instability that followed the collapse of Roman power in the region.
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Subsequently, the population was reconstituted from that reduced core. Using advanced molecular biology tools to date the origins of clan founders, the research identified that many current family lineages consolidated between the 14th and 15th centuries. Many oral traditions of shared ancestry, some hundreds of years old, are now verified through genetics, noted Athanasios Kofinakos, co-author and advisor on genealogical and historical matters of Mani. Geographic isolation and limited economic resources galvanized the warlike character of the locals. In such a hostile environment, family alliances became paramount for individual and collective survival.
Maternal lineages: a history of discreet integration
In contrast to the homogeneity of paternal lineages, mitochondrial DNA revealed significantly greater diversity. This pattern points to sporadic but constant contacts over the centuries with women from other areas of the eastern Mediterranean, the Caucasus, western Europe, and even North Africa. This disparity between paternal and maternal inheritance is consistent with the structure of a deeply patriarchal society, in which men remained anchored to the territory while a limited number of women from external communities were integrated through marriage.
These patterns are consistent with a strongly patriarchal society, in which male lineages remained locally rooted while a small number of women from external communities were integrated, explained the lead author, Prof. Alexandros Heraclides of the European University of Cyprus. Our study is the first to recover the untold stories of Maniot women, whose origins were largely obscured by male-centered oral traditions.
The genetic findings provide direct biological support for observations made by historical chroniclers. The Byzantine emperor Constantine VII Porphyrogenitus, in the 10th century, already noted the particularity of the Maniots, writing that they are not of the lineage of the Slavs, but of the Romans of old who were called Hellenes. The same historian recorded, as an extraordinary rarity, that the inhabitants of Deep Mani continued worshiping the Olympic gods well into the 9th century, in an Empire that had been fully Christianized for centuries.
The comparison of Maniot genomes with a database of more than one million modern individuals and thousands of ancient DNA samples, conducted by specialists at FamilyTreeDNA, confirmed their uniqueness. Researchers found almost no close matches with other populations, underscoring the degree of isolation and genetic distinctiveness that has characterized this community for more than a millennium.
The research team does not consider this study an endpoint, but rather a foundation for future investigations with potential clinical impact. Prof. Theodoros Mariolis-Sapsakos, co-author from the University of Athens and brother of Dr. Anargyros Mariolis, outlined the next steps: The team intends to collaborate again with the community to explore whether new genetic analyses in the population of Deep Mani may also be relevant for clinical and public health research, ensuring that scientific knowledge continues to benefit the people who made this study possible.
The research therefore transcends the realms of history and anthropology. By precisely mapping a population with such prolonged and well-documented genetic isolation, it opens an exceptional window for studying the interaction between genetic variation, demographic history, and disease susceptibility, offering a scientific legacy that honors the unique history of the Maniots of Deep Mani and their decisive contribution to understanding Europe’s complex history.
