DNA testing promises to provide genetic information to uncover details about one’s heritage.

More than a dozen companies now sell home DNA tests; the prices range from $100 to $900 each.

consumers also receive a document with their DNA string of markers, which looks like a list of numbers, and a report that explains how to make sense of it.

That data, however, needs to be compared with the data of others. For many consumers, that may mean recruiting other people, even strangers with similar last names, because the more corresponding numbers that two people share, the greater the chances that they share recent ancestors.