Discover Your Ancestry With DNA Tests

With the advent of new technology, DNA testing has become more popular not only with crime-fighters, but also with people who want to trace their family lineage.

With a swab of the inside of your cheek, you can learn where your original ancestors hailed from and the migration paths they followed. And National Geographic's Genographic Project, a multiyear study, has helped thousands of people from around the world take DNA tests to help show the ancestral connections we all share.

Interested? Here are four things to think about before DNA testing:

1. Your expectations of privacy. According to National Geographic, test results of those participating in the Genographic Project will remain anonymous. The project's ethical guidelines state that no medical research will be conducted using the test results, no patents will be applied for based on the research, and "samples collected will be held under strict conditions maintaining confidentiality and may not be used for any purpose inconsistent with the strictly limited scientific objectives of the project." Those objectives, according to project leader National Geographic Explorer-in-Residence Dr. Spencer Wells, are not to decipher information about individual participants' backgrounds, but to analyze historical patterns in DNA from participants around the world to better understand our human genetic roots. When the project is complete, all anonymous results will be shared in the public domain.

But the Genographic Project isn't the only option for studying your DNA. Private testing companies also offer the tests for genealogical purposes, with varying levels of privacy. For instance, Family Tree DNA assures confidentiality in its online privacy statement (laboratory workers will only see your last name and your unique testing number). But if you sign a release form and your DNA matches another test-taker's, who has also signed a release form, the company will provide you with each other's contact information.

2. What do you want to know? Because DNA tests show connections between people dating thousands, rather than hundreds, of years ago, you're more likely to learn about deep ancestral origins rather than recent family connections. One of the most helpful components of the test results is the information provided about a test-taker's haplogroup, which is, in a broad sense, ethnic background, or "the basic branch of the tree of humanity that your ancestors came from," says Bennett Greenspan, president of Family Tree DNA.

But the results can be surprising. For instance, Kathy Halvey, who has traced her ancestors to Scotland and England in the past few hundred years, expected her DNA test to classify her as haplogroup H, the most common haplogroup for those of European descent. But her DNA test classified Halvey as haplogroup J, which originated in the Middle East. According to her test results, Halvey's original ancestors were most likely Neolithic farmers in northern Iraq who migrated to Europe 10,000 years ago and taught Europeans how to farm.

3. Level of detail depends on other test-takers. If you're studying your family background on your own, DNA test results can sometimes provide recent clues -- if others in your family tree have also taken the test. For instance, private DNA testing companies such as Family Tree DNA maintain databases of all the people who have taken their tests, and your testing report will include information about others who match your results. For instance, after taking a DNA test, Family Tree will provide you with a list of people whose DNA matches yours, as well as your matches' countries of origin, along with a map showing the towns and villages of your matches' ancestral origin. Because most people know the country but not the city they come from, the maps show the specific locations to which other people with matching DNA have traced their ancestors to provide clues for new test-takers, says Family Tree DNA's Greenspan. In some cases, his company has even been able to match adoptees with biological family members, Greenspan says.

4. Different tests reveal different information. Various types of DNA tests are available, and the one you take will determine the information you uncover. For instance, the Y-chromosome test is the one most often used for genealogical purposes, but because it only tests portions of the Y-chromosome, which is only found in males, women cannot take the test. It is the only test that shows your patrilineal line of descent. The mitochondrial DNA (or mtDNA) test, on the other hand, reveals the female line of descent. Found in all humans, mtDNA derives only from a person's mother, as a father's mtDNA is lost during conception. So to get a complete picture of your family's ancestral roots, you may have to join with a brother, sister or cousins on each side of your family and take the tests together.

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