What can you learn from taking a DNA test?

The real answer to the question in the title of this post is it depends. But commonly, the answer is absolutely nothing. For example, telling me that I am 74% English is not surprising and after doing genealogical research for 38 years it is hardly new information. But before you start to respond with a list of all the things you learned from your own DNA test, hear me out.

A DNA test taken in isolation from its context is only useful when placed in the context with the purpose for which it was taken. If you take a DNA test for medical reasons, the test only becomes valuable when it is analyzed and interpreted in light of current medical research. If you take a DNA test for forensic reasons, it is only useful in the context of some type of legal action. If you take a DNA test to support genealogical research conclusions it is only useful if you have done careful and complete genealogical research. A more simple example is taking a DNA test from a genealogical database company. In that context, the results of your test are only useful if your test is compared to that of many other people taking the same test. In other words, the value of the DNA test is in the accuracy of the DNA matches. In my case, I have not learned anything that I did not already know.

If you start reading the flood of commentary on DNA testing, you will soon see that most of the comments relate to "discoveries"  that are made as a result of a DNA test taken in conjunction with a database of other people who have taken the same test. So far, the DNA tests that I've taken have matched me with a very small number of people who are classified as extended family. My own case, the number of people in this category is 11. Of those people, six do not have a family tree in the website providing the DNA test and since these people are living none of them appear in my family research. In short, I have no idea who these people are. So the fact that I am related to someone named "Sarah" is absolutely useless information to me. Granted, I could contact that person through the program but if she does not have a family tree how will she know how she is related to me?

In short, a DNA test is only valuable and only provides information if it is placed in the context of the research that it is intended to support. Again returning to the online stories about DNA testing, many of them relate how someone is surprised or even overwhelmed by learning that they have a certain ethnicity. But it is seldom emphasized that this conclusion comes only as a result of the DNA testing company having matched the results of the individual's DNA test to hundreds or thousands or even millions of other people taking the same test. But even with a database of millions of people, the DNA testing company will need to do careful research matching certain DNA sequences to people in a certain geographic area. If you took a DNA test some time ago, you have likely found that the results of your test have changed over time. This happens as a result of the DNA testing companies refining the results of the DNA tests as more and more tests are taken. So what happens if you based your actions or impressions on your initial test results received a year or two ago? Are you prepared to reassess your original impressions every time the DNA company refines and changes the percentages of ethnicity reported?

Another interesting fact is that despite the thousands of DNA matches I have received and continue to receive notice of, I have yet to have anyone contact me for genealogical information simply because of the DNA testing match. In those few cases when a person who has an extensive family tree matches to my DNA test, I almost certainly have already been notified through tree matching technology of that particular relationship. Granted, DNA testing may help to confirm that we both have fairly accurate research but without the extensive family tree research that preceded the test, the information would be essentially useless.

Hypothetical situation. But suppose that you were adopted and that you did not know either your birth mother for birth father. Let's further suppose that you take a popular DNA test. Will taking that test help you identify your birthparents? The answer is simple. Test results will only identify your birth parents if someone who is related to you, either your birthparents or another close relative, takes the same DNA test. So in that situation, if you were truly trying to find your birth parents, you would take every single test available. Doing so would increase the chances that one of your relatives had taken the same test. Granted, there are likely people out there who have done that, i.e. taken a series of DNA tests. But the companies who report the stories of people finding their relatives usually do not mention the fact that the person may have taken more than one DNA test.

The current DNA technology certainly increases the possibility that an orphan will find his or her birth parents or some other close relative. But it is my impression that reports of confirming extensive genealogical research conclusions only occurs when the people involved have been doing genealogical research extensively for many years. Meanwhile, what motivation do I have to contact Sarah who is a first cousin twice removed or fourth cousin who does not have a family tree?