Ancestry searches--do we only go for "far enough"?

Sometimes I wonder what people are thinking when they decide to research their ancestry. Is the goal finding someone important? Validating family stories? Proving connections to a particular "race"?

In the recent Newsweek article and the program on PBS, African-Americans, at least one person received different information about their ancestors than they were expecting. Most notable to me was the "Black man" who found he had no African heritage at all. A person whose letter was published in this week's Newsweek asked why nothing was said about repeating the surprised man's tests. That means that several others noticed that none of the presentations spoke about possible incorrect results.

Also interesting was the person who suddenly started wearing a Star of David upon learning of his Jewish heritage. This certainly suggests that some people change their behavior as a result of genetic testing--regardless of the accuracy of those tests. The common test sold in grocery and variety stores--the one that comes from Sciona--was featured several years ago in GeneWatch as a dubious product. Of course, the producers of Newsweek and PBS didn't identify the companies that did the tests. And we probably wouldn't have wanted that, considering the benefits of such free advertising.

Anyway, back to my main idea. What makes people trace their ancestry with a genetic test and when in the process do they stop? Anthropology and archealogy would both say that going "all the way back" brings us to an origin in Africa. But, many people stop once they've connected with a solid European (especially Western) heritage. If genetic tests are so good at telling people where they came from, how come they're comparing your DNA to someone's DNA collected in the past 10 years or so? Do we think that genetic changes occur worldwide and through time but can be ignored when the results say we're part of a group living today? Sounds a bit inconsistent to me.

By the way, just as with the chimpanzees, the differences between so-called races (or between chimps and humans) are many-fold smaller than the differences between two "Western European Caucasians" (or humans or chimps). Isn't amazing how we weight visible differences or even non-obvious differences (such as native language) much more than we do invisible factors?

Marie Godfrey, PhD