Your Personal Genetic Guide to Ancestry DNA Tests

At-home DNA tests help to provide insights to your family tree and genetic makeup. Whether you are a curious adoptee or academic researcher, the promise of learning more about who you are and where you come from is enough to entice anyone to give a try. Before you do, let us introduce you to the science behind the test in order to give you a better idea of what to expect.


How It Works, Basically

Ancestry DNA tests work by analyzing sequences in human DNA. Certain patterns in the structure of your DNA allow trained experts to determine what geographic region your genetic information originated. They can determine this because these genetic templates do not change much between generations. The information provides a supplement to what we already know about a person’s family tree.

Ancestry DNA tests are by no means an exact determination from whom and where you descended, but rather an approximate determination. Each company that performs these tests are working from a different database of genetic information, so results may vary between labs. As the service obtains further records, it may be able to tell you more about your genetic past.

When Vanessa Williams took the genome test, it turned out her DNA was approximately: 23% Ghana; 17% British Isles; 15% Cameroon/Congo; 13% Finnish/Ural/Volga; 11% southern European; 7% Togo; 6% Benin; 5% Senegal; 4% Spain/Portugal. This helped to explain the presence of a rare blood disease in her family that normally occurs only in Southern European populations, where she has roots.


Controversy Over Genetic Testing

Since scientists introduced the technology around 2005, there has been marked controversy over how much they can actually tell you. Most of these DNA tests break down where your ancestors came from into a percentage. However, they cannot tell you if you are descended from Napoleon, or any other ancestor further back than about five generations. That’s when the waters get too murky.

As a Leslie O’Hanlon concluded in the MIT Technology Review during February 2006, “If a test suggests that I have lineage in Ghana, I’m not going to all of a sudden start calling myself a Ghanaian. Nevertheless, I will have a small bit of information about some of my ancestors. And that’s well worth knowing.”

Others worry how these companies will use your DNA sample in the future. Most of these companies have not made their data sets available to the general public yet, but that is not to say they won’t soon. There is not a lot of precedence for such a situation, and there are concerns about issues of privacy.

At Ancestry.com, interested parties are able to download their own genetic information. But, the service notes that once you do, the highly personal data will no longer be protected by their encrypted security system.


Types of DNA Tests

The trick to finding out what you want to know is understanding the different types of DNA tests and how they work. By comparing and contrasting the expected results with what you already know, you can determine the best DNA test to gain insights to your genetic past. Be sure to see what type of test a company offers before sending off your sample.


Mitochondrial (Maternal)

A mitochondrial DNA test, or an MtDNA test for short, examines the DNA that is passed down from a mother to her children. Since MtDNA remains much the same through each generation, it is a good indicator of ethnic origin on your mother’s side, and her mother’s, and so on. It is a limited scope through your maternal relatives only, which is a narrow window in comparison to your entire genome. This type of test is useful for anyone interested in uncovering more about their maternal lineage, especially if you already have strong historical records.


Y-Chromosome (Paternal)

A Y-Chromosome DNA test (ST-DNA test) can only be taken by men, because only the male gender has y-chromosomes. If you do not have any y-chromosomes, try asking a close male relative to swab his cheek with a Q-Tip. The Y-chromosomes remain remarkably unchanged from generation to generation and family member to family member. In this way, it is a lot like the MtDNA test, except that it travels down the opposite pathway. You can even have your paternal DNA recorded in a Surname DNA project so that your bloodline may continue.


Autosomal (Both)

A human being has 23 chromosomes. An autosomal gene is any of the 22 chromosomes that are not sexual.  It follows that during an autosomal DNA test, both male and female relatives can be detected. This type of test is more comprehensive than the first two, because it can trace back DNA patterns as far as five generations. However, it cannot tell you which family members are from what branch of the tree, unless you do further research and investigation. 


Other Kinds of DNA Tests

Geneticists can provide you with a number of insights to various details of your family’s past using the right DNA tests. For example, a CCR5 test can tell you if your ancestors survived the Black Plague by looking for a characteristic mutation. According to Family Tree, the modern human is approximately 2% neanderthal DNA, implying that your cave people ancestors reproduced with a neanderthal. Tests can also reveal facts about your proclivity to certain diseases, tolerance for alcohol, nicotine, or caffeine, and whether you carry the warrior gene.


Top DNA Test Providers


  • 1. AncestryDNA

- Provider: Ancestry.com

  • 2. Geno 2.0

    • - Provider: National Geographic

    • - Origin: Washington, D.C.

    • - Type: Y-Chromosome

    • - Cost: $199.99

  • 3. 23 and Me

    • - Provider: 23 and Me, Inc.

    • - Origin: Mountain View, CA

    • - Type: Mitochondrial

    • - Cost: $99

  • 4. Family Tree DNA

    • - Provider: Gene By Gene, Ltd.

    • - Origin: Houston, TX

    • - Type: Most types of DNA tests available.

    • - Cost: $58-$566   

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