Recent work by geneticists, involving the DNA of more than 50,000 volunteers on three continents, suggests some inferences about the Trans-Atlantic slave trade from 1525 to 1866. For the most part, the genetics confirms the understandings that historians have developed from the available records. But in some respects, the genetics corrects conceptions those records alone suggest.
The gene research indicates that people of African descent in North and South America have greater connections to the present day Democratic Republic of the Congo and to Angola than to other parts of Africa. And this is consistent with what one could infer from the shipping manifests. Of the 12.5 million people enslaved and brought across the Middle Passage, 5.7 million were from the region represented by those two countries today.
Strange New Worlds:
On the other hand, the geneticists found far sparser links to Senegal and Gambia than historical records would suggest. Why? One hypothesis is that the slaves from those countries were often taken to rice plantations in the Americas. Rice plantations had very high mortality rates, so the Senegalese/Gambian gene lines may have been winnowed out early.
The study appeared in the American Journal of Human Genetics.