The origins of the populations of the Cape Verde Islands, a former hub of the African slave trade, have been virtually erased from history. But past interbreeding has left genetic and linguistic imprints, allowing scientists to trace back time, according to a study published Tuesday, April 25 in the online journal e-Life.
The Atlantic archipelago was the first European settlement in sub-Saharan Africa. When the first Portuguese settlers arrived in the 15th century, the territory was uninhabited. A strategic point off the coast of Senegal, on the road to the Americas, Cape Verde then became, from the 16th century, a bridgehead for the transatlantic slave trade until its abolition in the 19th century. Slaves from the African continent were deported there en masse, to work on the plantations or to be sold across the ocean. This has given rise to a number of interbreeding between enslaved and non-enslaved communities, from which the Cape Verdeans come.
But due to a lack of historical records, very little is known about their ancestors. "One of the violence of enslavement was the erasure of roots to prevent people from finding their origins," Paul Verdu of the Eco-anthropology laboratory (CNRS-Musée de l'Homme), who led the study.
Early crossbreeding
To fill these gaps, an international team left in 2010 on the genetic and linguistic traces, by taking the DNA of 261 people speaking Kriolu, the local Creole, on the nine inhabited islands of the archipelago.
Thanks to artificial intelligence methods and tools, they were able to compare the genetic data collected with those of populations from the Iberian Peninsula, to find their commonalities. And trace the old interbreeding.
First conclusion: this interbreeding began very early, between the first generations of colonizers and the first deported slaves. Until the 16th century, they were made mainly between Iberian populations and certain populations of the Senegambian region (current Senegal and Gambia).
These results surprised the researchers, who expected to find more genetic diversity in view of the intensity of migrations that took place through the ages. “On the European side, there was also English immigration [part of the islands was under their domination], French; on the African side, slaves deported from Senegambia but also from Congo, Angola and even Mozambique (ex-Portuguese colonies)... Without however leaving a trace of their genes", explains Paul Verdu.
These populations without or almost no descendants nevertheless marked the culture, since they left words in the Creole lexicon. By listening to the 261 Cape Verdeans speak, according to different linguistic protocols, the researchers have indeed found the mark of the Bantu languages of the Congo or Angola, develops this anthropologist and population geneticist.
Second conclusion, also surprising: interbreeding marked time between the second half of the 17th and 18th centuries. Which may seem paradoxical because it was during this same period that the slave trade exploded. "We go from ten thousand individuals deported per year to several tens, even hundreds of thousands with the rise of the plantation economy around 1640", underlines the researcher.
Stricter segregation
Although more numerous, the slaves therefore "did not make many babies". No doubt because they were quickly deported to the Americas, unlike previous generations who had settled more permanently on the archipelago.
Another hypothesis: with the intensification of the slave trade, a stricter separation between masters and slaves developed. “We are in full swing with the Code Noir at the end of the 17th century, which establishes uses of segregation in the European colonies. Masters create slave barracks and seek to control marriages within enslaved communities,” Paul Verdu points out.
On the other side of the Atlantic, the reverse has happened, he notes: according to the genetic data of the more widely studied African-American populations, the intensification of interbreeding has coincided with the explosion of the transatlantic slave trade.
"We often see the history of slavery as a monolithic block, yet genetics teaches us a great diversity of stories", concludes the scientist.
