Editor’s note: This article was originally published on Aug. 1, 2014.
Dear Professor Gates:
I am very much a “white” person, with no family oral history to suggest otherwise (except the obligatory Native American-ancestor stories, which don’t pan out).
However, when I had a test done for myself by Ancestry DNA, my results came back with around 1 percent African DNA. When painting my chromosomes [to visually highlight relevant areas], I found a moderate-sized segment that comes up sub-Saharan African on all data sets, about 7-8 centimorgans or so.
I had my parents tested, and the same segment shows on my mother’s DNA, except hers is about twice as large, roughly 15-17 cM (she also had a couple of other smaller segments that were African). She also comes up anywhere between 0.8-1.3 percent African (more of that sub-Saharan than what I have). I seem to get some North African/Middle Eastern from my father, who had traces of it in his own test results, but mostly continental European ancestry.
I had a DNA expert look into it further. His first discovery was that the sub-Saharan African result is definitely legitimate and not just noise. When he ran the data further, he found that it matched most strongly from East Africa (the highest match being 1.5 cM to a Masai data sample, as well as multiple other matches). At first he thought it would be from a nearby area, maybe the Near or Middle East or the Mediterranean. As he dug further, he didn’t see it matching any of those nearby regions, and to his surprise, it seemed to suggest that I have an East African ancestor in the last couple hundred years.
I was able to narrow this down to my mother’s father (I had my grandmother tested, and it doesn’t show any of those segments). The paper trail dates back at least 200 years or so without any immigrant ancestors, and everyone we’ve traced shows as “white” on census records, though it’s worth noting that all the people in this branch of my family tree were living in the South.
At first when I saw African DNA, I thought I might have a slave ancestor, though with East African results, I’m a bit at a loss. I’m curious if you know of any reason a “white” American with at least 200 years of American ancestry might have East African DNA. —Matthew Langley
It is certainly possible for you to have an East African ancestor, though you are correct in noting that most enslaved Africans didn’t come from that region. Most of those who did weren’t brought to America.
The Trans-Atlantic Slave Trade Database, headed by David Eltis and Martin Halbert, shows just over 542,000 people embarking from Southeast Africa and a few Indian Ocean islands between 1601 and 1866—just a small fraction of the 12.2 million people who were enslaved and taken from Africa during that period.