Ancient DNA restores the origin story of the Swahili people of the East African coast

The legacy of the medieval Swahili civilization is a source of extraordinary pride in East Africa, as evidenced by the language that is the official language of Kenya, Tanzania and even inland countries such as Uganda and Rwanda, far from the coast of the Indian Ocean where the culture almost developed. two millennia ago.

The graceful stone and coral cities hugged 2,000 miles of shore, and the merchants played a pivotal role in the lucrative trade between Africa and countries across the ocean: Arabia, Persia, India, Southeast Asia, and China.

By the turn of the second millennium, the Swahili people embraced Islam, and some of their great mosques are still on UNESCO’s World Heritage Sites Lamu in Kenya And Kilwa in Tanzania.

Self-rule ended after Portuguese colonization in the 1500s, with control later shifting to the Omanis (1730-1964), Germans in Tanganyika (1884-1918), and British in Kenya and Uganda (1884-1963). After independence, the coastal peoples merged into the modern nation-states of Somalia, Kenya, Tanzania, Mozambique, and Madagascar.

So who were the Swahili people and where did their ancestors originally come from?

Ironically, the Swahili ancestry narrative has been shaped almost entirely by non-Swahili people, a challenge shared by many other marginalized and colonized peoples who are the modern descendants of past cultures with extraordinary achievements.

In collaboration with a team of 42 colleagues, including 17 African scientists and several members of the Swahili community, we have now first ancient DNA sequences of peoples of the Swahili civilization. Our results do not provide simple validation of the narratives previously put forth in archaeological, historical, or political circles. Instead, they contradict and complicate them all.

Colonization affected the way the story was told

Western archaeologists in the mid-20th century emphasized the connections of medieval Swahili with Persia and Arabiasuggests that sometimes their impressive performance couldn’t have been reached by Africans.

Postcolonial scholars, including one of us (Kusimba), pushed back against that position. Previous researchers had exaggerated the importance of non-African influences by focusing on imported objects at Swahili sites. They minimized the vast majority of locally made materials and what they revealed about African industry and innovation.

But viewing Swahili heritage as primarily African or non-African is too simplistic; In fact, both perspectives are by-products of colonialist prejudices.

The truth is that the colonization of the East African coast did not end with the departure of the British in the mid-20th century. Many colonial institutions were inherited and perpetuated by Africans. As modern nation-states were formed, with governments controlled by inland peoples, Swahili people continued to undermine politically and economically, in some cases as much as under foreign rule.

Decades of archaeological research in consultation with local people aimed to address the marginalization of Swahili-descended communities. Our team consulted oral traditions and used ethnoarchaeology and systematic investigations, along with targeted excavations of residential, industrial and burial sites. Working with local scholars and elders, we excavated materials such as pottery, metal and beads; food, home and industrial remains; and imported items such as porcelain, glass, glass beads and more. Together they revealed the complexities of everyday life in Swahili and the cosmopolitan heritage of the people of the Indian Ocean.

Ancient DNA analysis has always been one of the most exciting prospects. It offered the hope of using scientific methods to find answers to the question of how medieval people relate to past groups and to people of today, and offered a counterweight to stories that were imposed from outside. Until a few years ago, this kind of analysis was a dream. But because of one technological revolution in 2010the number of ancient people with published genome-scale data has gone from nothing to today more than 10,000.

Surprises in ancient DNA

We worked with local communities to determine best practices for handling human remains in accordance with Muslims’ traditional religious sensibilities. Excavations of cemeteries, sampling and reburial of human remains were carried out in one season, instead of dragging on endlessly.

Our team generated data from more than 80 people, mostly elite individuals buried in the wealthy centers of the stone cities. We will have to wait for future work to understand whether their genetic heritage differed from those without their high status.

Contrary to what we expected, the ancestry of the people we analyzed was not largely African or Asian. Instead, these backgrounds were intertwined and each contributed about half of the DNA of the people we analyzed.

We found that Asian ancestry came largely from Persia (present-day Iran) in medieval individuals, and that Asians and African ancestry began to mix at least 1,000 years ago. This photo is almost a perfect match with the Kilwa chroniclethe oldest story told by the Swahili people themselves, and almost all of them previous scholars had dismissed like some kind of fairytale.

Another surprise was that, mixed with the Persians, Indians made up a significant portion of the first migrants. Patterns in the DNA also suggest that Asian immigrants became increasingly Arab after the transition to Omani control in the 18th century. Later, there were mixed marriages with people whose DNA was similar to others in Africa. As a result, some modern people who identify as Swahili have inherited relatively little DNA from medieval peoples like those we analyzed, while others have more.

One of the most revealing patterns our genetic analysis identified was that the vast majority of male ancestry came from Asia, while female ancestry came from Africa. This finding must reflect a history of Persian men traveling to the coast and having children with local women.

One of us (Rich) initially hypothesized that these patterns might indicate Asian men forcibly marrying African women, as similar genetic signatures are known to exist in other populations reflect such violent histories. But this theory does not explain what is known about the culture, and there is a more likely explanation.

Traditional Swahili society is similar to many other East African Bantu cultures essentially matriarchal – it puts a lot of economic and social power in the hands of women. In traditional Swahili societies even today ownership of stone houses often goes along the female line. And there is a long recorded history of female rulers, beginning with Mwana Mkisi, ruler of Mombasa, as recorded by the Portuguese as early as the 1500s, to Sabani binti Ngumi, ruler of Mikindani in Tanzania as late as 1886.

Our best guess is that Persian men connected to and married into elite families and adopted local customs to enable them to become more successful traders. The fact that their children passed on their mothers’ language, and that encounters with traditionally patriarchal Persians and Arabs and conversion to Islam did not change coastal African matriarchal traditions confirms that this was not a simple history of African women being exploited. African women preserved critical aspects of their culture and passed it down through generations.

How do these ancient DNA results restore heritage for the Swahili? Objective knowledge about the past has great potential to help marginalized peoples. By making it possible to challenge and overthrow narratives imposed from outside for political or economic ends, scholarly research provides a meaningful and undervalued tool for righting colonial wrongs.