DNA Test: 'Unknown' Ancestry?

Tracing Your Roots: A reader with a rare disease wonders if retesting will provide insights.

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(The Root) --

"I was recently diagnosed with an uncommon autoimmune disease called Vogt-Koyanagi-Harada (VKH) syndrome, which is found in Asians, Mediterranean people and Native Americans. I am African American. I had my DNA tested via Ancestry.com's AncestryDNA test and was told that I was 68 percent West African, 25 percent Central European and the rest Unknown. 

I know that VKH is hereditary. I am worried for my children. Should I assume that the 'Unknown' percentage is Native American or should I have the test done again? My parents migrated from the Carolinas, where their families lived for generations." --Yvonne Deal Chandler

First of all, I am sorry to hear that you are dealing with this rare inflammatory condition, which can affect the skin, hair, eyes and other organs containing melanin-producing cells. According to Joanna Mountain, a geneticist and senior director of research for the ancestry DNA service 23andMe, the syndrome you have "is known to occur in African Americans, so getting better ancestry information is not likely to provide new insights."

Beyond your worries for your children, for whom I wish the best, you may still wonder about the Unknown result and whether it is, in fact, Native-American ancestry. We asked Ken Chahine, senior vice president of Ancestry.com, what the result of your autosomal DNA test (also known as an admixture test) could mean, and he told us, "The Unknown [result] is a 'bucket' of all ethnicities that are less than 5 percent [of the total]. You cannot assume that it is Native American. In the next version [of the test] we will allow you to look at the ethnicities that are less than 5 percent."

So, as the AncestryDNA results clearly indicate, it is highly unlikely that you have a significant amount of Native-American ancestry.

Henry Louis Gates Jr. is the Alphonse Fletcher University Professor and the director of the W.E.B. Du Bois Institute for African and African-American Research at Harvard University. He is also editor-in-chief of The Root. Follow him on Twitter.

Send your questions about tracing your own roots to TracingYourRoots@theroot.com.

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