What is your DNA?

Mr. Gates, director of the W.E.B. Du Bois Institute for African and African American Research at Harvard, said his experience and similar stories from others have prompted him to enter the field.

Mr. Gates recently teamed up with Family Tree DNA, a DNA testing and genealogy firm in Houston, to provide genetic testing and genealogy work for African-Americans. The new venture is called AfricanDNA.

“What we hope to do is combine this with genealogical and other records to try to help people discover their roots,” he said. “The limitations of current genetic DNA tests mean you can’t rely on this alone to tell you anything. We hope to bring a little order to the field.”

In an editorial in Science magazine in October, a number of scientists and scholars said companies might not be fully explaining the limitations of genetic testing, or what results actually mean.

The authors said that limited information in the databases used to compare DNA results might lead people to draw the wrong conclusions or to misinterpret results. The tests trace only a few of a customer’s ancestors and cannot tell exactly where ancestors might have lived, or the specific ethnic group to which they might have belonged. And the databases of many companies are not only small — they’re also proprietary, making it hard to verify results.

“My concern is that the marketing is coming before the science,” said Troy Duster, a professor of sociology at New York University who was an adviser on the Human Genome Project and an author of the Science editorial.

“People are making life-changing decisions based on these tests and may not be aware of the limitations,” he added. “While I don’t think any of the companies are deliberately misleading customers, they may have a financial incentive to tell people what they want to hear.”

Bennett Greenspan, founder and president of Family Tree DNA, said his company sometimes has to tell clients just the opposite. “We’ll have people who may think that they have a certain type of ancestry and we’ll tell them based on the test they are not,” he said. “I can only tell them what the tests show, nothing more. And sometimes it’s not what they want to hear.”

I comment with words written two centuries ago:

..."It is a humiliating confession, but we are all of us made out of the same stuff.
Where we differ from each other is purely in accidentals: in dress, manner, tone of voice, religious opinions, personal appearance, tricks of habit and the like. The more one analyses people, the more all reasons for analysis disappear. Sooner or later one comes to that dreadful universal thing called human nature."