Swahili Coast was already connected well before Vasco da Gama – 03/30/2023 – Science

Centuries before Vasco da Gama and other Portuguese navigators landed in East Africa, the region’s coastline was already connected to global trade networks. Marks of this are in the DNA of ancient inhabitants of the region, shows a new study: almost all of them seem to descend from the union of Africans and travelers of Persian, Indian and Arab origin.

According to the calculations of the team responsible for the research, this process would have gained strength around the year 1000 AD, a period that coincides with the advance of Islam in the region. Although genomic data were obtained from archaeological sites in Tanzania and Kenya, it is likely that the ancient miscegenation between Africans and merchants from the Middle East and India also covers areas such as Mozambique (one of the sources of people enslaved for the slave trade in Brazil ).

The new data have just come out in an article in the scientific journal Nature. The work was coordinated by David Reich, from Harvard University (USA), and Chapurukha Kusimba, from the National Museums of Kenya.

The duo and their collaborators obtained genetic material from 80 individuals who died in six coastal cities in the region and one inland location, dating from the Middle Ages (around 1250), through the so-called Age of Discoveries and up to 1800, a few decades before the region became a colony of the British Empire.

From the 19th century, the area encompassed by the study became known as the Swahili coast, because of the predominance of the language of the same name there. Swahili is indisputably an African language, part of the large group of Bantu languages ​​(also present in Congo, Angola, South Africa and elsewhere). At the same time, it incorporates a large number of words of Arabic origin —starting with the very name of the language, which means something like “from the coast” in the language of the Koran— and Persian, among other influences.

Everything indicates that the connections between the Swahili coast and the great trade routes of the Indian Ocean are quite old, dating back at least to the 7th century AD It was when the coastal communities of the region, before simpler, dedicated to fishing and agricultural work, began to become cities and began to receive products by sea more intensively.

Traders from Asia were interested in typically African luxury products, such as elephant ivory, but also in gold, coming from more distant regions abroad. Trafficking in enslaved people also took place along this route. Navigation was facilitated by winds that blew to the southwest from March to October, taking ships from the Middle East and India to East Africa, and then to the northeast from November to March, even allowing merchants to return in the same year of the trip, with any luck.

When studying the genetic material of people from the Middle Ages and the Age of Discovery, researchers used two main approaches. On the one hand, they made a general estimate of the contribution of different populations to their DNA—roughly, the “mixing” of fathers and mothers over time.

In addition, they analyzed two types of genetic material that do not enter this mix, but are normally transmitted directly in each person’s lineage. In this case, we are talking about the Y chromosome, the genomic mark of the male sex, usually transmitted only from father to male child; and mtDNA or mitochondrial DNA, which only exists inside the mitochondria, the power plants of cells. mtDNA is only transmitted on the mother’s side, from mother to daughter or son.

Based on this, the researchers found that, on average, the ancient inhabitants of the Swahili coast had just over half of their “global” DNA with African origin, while the rest was linked mainly to ethnic Persian populations (in present-day Iran), including even a small Indian contribution and, in rarer cases, Arab. This pattern just does not appear in the interior populations.

On the other hand, the Y chromosome and the mtDNA show exactly how this miscegenation took place. Over 80% of men on the former Swahili coast carried a typical Middle Eastern Y chromosome, while over 95% of people in the region at that time had typically African mtDNA. In other words, everything indicates that the union between (almost always) Persian men and African women ended up giving rise to the Swahili culture over time.

Historical records from Kilwa, one of the main cities in the region in the Middle Ages, in fact speak of the arrival of navigators from the Persian province of Shiraz. Coins found in Kilwa indicate that a nobleman of Persian origin named Ali bin al-Hasan would have become ruler of the city around the year 1050. Immigrants would have driven urban transformations in the region, such as the construction of mosques and Islamic tombs using coral as material -cousin.