The recent article in The Root by Boston University historians Linda Heywood and John Thornton generated considerable interest in their groundbreaking findings that most American blacks are descended from just 46 ethnic groups and three major regions of Africa.
In a follow-up interview, they explain the process they used to reach their results and the significance of those findings for African Americans in search of their ancestry.
The Root: Your article for The Root described how the majority of African Americans originated with just 46 ethnic groups in Africa from three major regions. What is the significance of those findings?
John Thornton and Linda Heywood: By showing how concentrated the slave trade was, in just a few regions of Atlantic Africa, we can bring more attention to the exact historical processes that caused people to be enslaved. The histories of these areas are fairly well-known among historians specializing in African history, for example, and we can name rulers, outline the course of wars, discover trading patterns and learn about judicial systems in the areas.
We can also see in detail how relations between Africans and Europeans changed over time, and how this, in addition to changes in African politics, resulted in the capture, enslavement and export of some African groups and not others.
TR: What impact does the narrowing of origins have on the efforts of African Americans to trace their origins?
JT and LH: At the present time, DNA results often produce matches with people living in different regions of Africa, some of which never participated in the Atlantic slave trade. We can discount results that point to Cameroon, South Africa or Ethiopia, for example; few or no enslaved Africans from these regions came to North America during the period of the slave trade.
On the other hand, we favor results that indicate Angola, Nigeria or Senegal connections, as these were areas that supplied the majority of slaves to the United States. It will also allow researchers who are seeking to identify populations to target these areas to collect samples, and thus expand the pool of potential African relatives of African Americans.
TR: Is there often a gap between the oral history in families and the actual DNA results of many African Americans?