DNA Genealogy: Combining Science with Searching

I don’t watch crime dramas on TV. They give me nightmares. If you do watch them, you’re probably familiar with how DNA can help solve crimes. DNA testing is also becoming a popular method of research among genealogists and lay-people working on their family trees. There are an increasing number of companies offering DNA tests for use with genealogy work.

It can be confusing to know which company to choose or which type of testing to pursue if you’d like to use DNA to expand your family search. Here are the basics of DNA genealogy:

What Is DNA?

DNA is the basic genetic material in every person’s cells that determines every one of their physical characteristics. Part of a person’s DNA comes from their father and part of it comes from their mother. It’s the stuff that gave you your mom’s nose and your dad’s hair color.

Types of DNA Tests Useful for Genealogy:

Y-DNA Tests (also known as Paternal Tests): These tests provide information about a family’s paternal line. This test looks at specific DNA markers on the Y chromosome. Women don’t have Y chromosomes, so this is a test that only men can take. The markers that this DNA test reports will be the same or extremely similar in all of the men in a paternal line. Companies test differing numbers of these markers, and the more markers that are reported, the more specifically the test can compare your DNA to others’.

This test is useful for confirming that two men share a common ancestor. However, by itself, Y-DNA testing can’t identify that common ancestor. If your paper genealogy trail suggests that two men are related and you would like to confirm it, you could have both men take this test to verify your suspicion. Otherwise, your test results must be compared to those of others to find potential matches, and the more people who have submitted test results, the better.

Surname projects are organized databases that bring together the results of many men with the same last name who have had Y-DNA testing done. This can help determine how the men are related to one another. Googling your last name + “surname project” can help you find and join these databases.

Mt-DNA Tests: These tests evaluate mitochondrial DNA. This type of DNA is passed from a mother to her children (both males and females), mostly without any changes. This information can help you to trace your maternal lineage back through the ages.

I find it super fascinating that you can use Mt-DNA to follow your mother’s line back to one of the “clan mothers.” These were a handful of ancient women all over the globe that every person living today can be connected back to through their maternal lines. Each of these clan mothers can then be traced further back to one woman who lived in Africa about 140,000 years ago.

This test is useful for people who are interested in tracing their maternal lineage, and for people who would like to learn the geographic origins of their maternal line.

Autosomal DNA Tests: Autosomal DNA is the type of testing that is used to help solve crimes. But tests used by genealogical companies look at many more markers than crime labs do, since the ultimate goal is not to match the subject DNA to the DNA of the same person, but to compare it to the DNA of others.

Autosomal DNA is found on all of a person’s chromosome pairs and is inherited from both parents and all four grandparents. You can search for connections along any branch of your family tree with this test, but relatives from the distant past will often not share any autosomal DNA with you, due to the constant mixing up of the genes and the random way that they are combined to create a new person (known as recombination). So the autosomal DNA test is best for identifying fairly close relationships.

This test gives you the most information when your results can be compared with those of as many other people as possible.

Which DNA Testing Company Should You Choose?

Once you know which type of test you would like to pursue, research a variety of companies’ offerings, the tools that they have available for you to utilize the results once you have them, and the associated costs. The International Society of Genetic Genealogy has information on their website about the different DNA testing companies and what they offer:

• Y-DNA testing comparison chart
• Mt-DNA testing comparison chart
• Autosomal DNA testing comparison chart

How Can You Use Your DNA Test Results?

Once you have your DNA results, there are lots of ways you can use them. The companies themselves have databases that can search for matches for you. If the company that you use allows it, you can take your results and submit them to other companies or databases. Ideally, casting the widest net by doing all three types of testing and submitting the results to as many databases as possible will garner the most information for you to further your genealogy efforts.

Whether you wish to explore paternal ancestry, ancient maternal lines, or closer branches on your family tree, DNA tests can help you validate your paper genealogy results and move you forward in your search.

I haven’t taken the DNA testing leap yet, but there are so many fascinating ways that it can add to my genealogical research, that I’m sure it’s something I’ll be pursuing in the near future.