Genetic impact of African slave trade revealed in DNA study
A major DNA study has beamed new light on the fate of millions of Africans who were traded as slaves to the Americas between the 16th and 19th centuries.
The genes of 50,000 descendants of slaves reveal the effects of the global slave trade generations later, according to a study published in the American Journal of Human Genetics. Researchers analyzed data provided by thousands of 23andMe customers who agreed to share their genetic information to better understand the impact of forced migration on the genealogy of the descendants of enslaved Africans in the Americas.
A video documentary by BBC reveals how it all started.
They found that enslaved people who were brought from one African region to a particular region in the Americas generally ended up sharing a genetic connection to that African region generations later, said Steven Micheletti, a population geneticist with 23andMe and the first author of the study.
It lays bare the consequences of rape, maltreatment, disease and racism.
More than 12.5m Africans were traded between 1515 and the mid-19th Century.
Some two million of the enslaved men, women and children died en route to the Americas.
The DNA study identified more details of the “genetic impact” the trade has had on present-day populations in the Americas.
While much of their findings agreed with historical documentation about where people were taken from in Africa and where they were enslaved in the Americas, “in some cases, we see that they disagree, quite strikingly”, he added.
The study found, in line with the major slave route, that most Americans of African descent have roots in territories now located in Angola and the Democratic Republic of Congo.
What was surprising was the over-representation of Nigerian ancestry in the US and Latin America when compared with the recorded number of enslaved people from that region.
Researchers say this can be explained by the “intercolonial trade that occurred primarily between 1619 and 1807”.
They believe enslaved Nigerians were transported from the British Caribbean to other areas, “presumably to maintain the slave economy as transatlantic slave-trading was increasingly prohibited”.
Likewise, the researchers were surprised to find an underrepresentation from Senegal and The Gambia – one of the first regions from where slaves were deported.
Researchers put this down to two grim factors: many were sent to work in rice plantations where malaria and other dangerous conditions were rampant; and in later years larger numbers of children were sent, many of whom did not survive the crossing.
In another gruesome discovery, the study found that the treatment of enslaved women across the Americas had had an impact on the modern gene pool.
Researchers said a strong bias towards African female contributions in the gene pool – even though the majority of slaves were male – could be attributed to “the rape of enslaved African women by slave owners and other sexual exploitation”.
In Latin America, up to 17 African women for every African man contributed to the gene pool. Researchers put this down in part to a policy of “branqueamento”, racial whitening, in a number of countries, which actively encouraged the immigration of European men “with the intention to dilute African ancestry through reproduction”.
Although the bias in British colonised America was just two African women to one African man, it was no less exploitative.
The DNA study highlighted the “practice of coercing enslaved people to having children as a means of maintaining an enslaved workforce nearing the abolition of the transatlantic trade”. In the US, women were often promised freedom in return for reproducing and racist policies opposed the mixing of different races, researchers note.
As Statues of colonial-era slave traders been pulled down by protesters demanding an end to the glorifying of symbols of slavery, is there any positive impacts on The Black Lives Matter movement lighting on the damaging legacy of colonialism and slavery on African Americans and other people of African heritage around the world?