Putting the Gene Back in Genealogoy

My own brick wall started to materialize about three years ago, when my then 87-year-old maternal grandfather, Robert Lee, decided it was time to pass on a piece of family lore. It was a tale he’d kept to himself since one night in 1942, when he sat with his aunts as they rocked slowly in their chairs after supper, spinning family stories. Grandma Elenor Hickenbottom, one of them whispered, she was a black woman. This was the early 1940s in southern Illinois—a time and place when people whispered about things like mixed race, if they talked about it at all. My grandfather searched out and found Elenor’s grave—a small stone hidden in the woods behind the church—and visited it each year without fail, but he didn’t speak a word of her existence for nearly 60 years. “It’s something I’ve wanted to talk about for a long time, but I couldn’t,” he told my mother and her brothers. “My brother Ronald and I were the only ones who admitted the truth; now he’s dead, so I just have to tell you, even if it makes you mad.”



Of course, it didn’t make us mad—just curious. Were we truly descended from an African-American woman? Where had she come from? Had she been a slave? Unfortunately, the paper trail was useless in this case—in part because no one knows Elenor’s maiden name; whenever she appears
in historical documents, it’s by first name only. As circumstantial evidence in support of my grandfather’s story, this omission is actually compelling: Many African-Americans who ended up in Illinois were born in the South with no birth certificate, fled north to freedom, and proceeded through life without documentation. Circumstantial evidence, though, hardly constitutes proof.


But what if the proof resided elsewhere? What if it resided within my family’s cells?

I settled on two companies to run the tests. I chose the first—Florida-based DNA Print Genomics—because it developed and is the main supplier of the one test that analyzes a person’s DNA for evidence of ethnic heritage. The company would tell me what percentage of my DNA (if any) was Native American, Indo-European or African. The second company—Family Tree DNA—offered the largest selection of tests and claimed the greatest accuracy by testing more genetic markers than anyone else. Family Tree DNA was also the only company offering to find real flesh-and-blood “long-lost relatives” for me—not exactly the object of my inquiry, but intriguing nonetheless.


To understand the tests these companies and their competitors offer, it’s important to first ground yourself in some basics. Different tests rely on different kinds of DNA. One, nuclear DNA, is what most people think of when they imagine DNA—it’s passed from mother and father to child and influences everything from eye color to height. Each strand of nuclear DNA is a sequence of more than 3.2 billion letters (all either A, T, G or C). Nearly 99.9 percent of that sequence is identical in all humans, but 0.1 percent varies in specific locations on the genome—a T changed to a C or a G to a C. These differences account for the vastness of human diversity. Most of these mutations are single nucleotide polymorphisms, or SNPs (“snips”)—generally harmless changes that occur spontaneously and are passed from generation to generation. Some populations, Africans among them, evolved in particularly isolated groups, passing unique SNPs on to each generation. Over time, this created what scientists call “ancestry-informative markers,” particular SNPs where, say, West Africans are more likely to have a C and Europeans are more likely to have a T. These ancestry-informative markers are what DNA Print Genomics uses to determine what percentage of four ethnic groups each customer descended from.