Which DNA Test Should I Take?

We are pleased to introduce our new genetic genealogy guest blogger, Robin Wirthlin. Robin has a B.S. in Molecular Biology from BYU and a Certificate in Genealogical Research from Boston University. Robin loves to use genetic genealogy to solve family history mysteries and break through “brick walls.” We hope you enjoy the first of her series of genetic genealogy posts!

-Diana and Nicole

An exciting type of information that can be used to identify and connect family relationships is DNA evidence. DNA, which is short for deoxyribonucleic acid, is the genetic code carried in each of the cells in our bodies. It has always been with us and has been passed down from our ancestors throughout the millennia. Recently, DNA testing has become more and more available and affordable – and popular because of mass media advertising. Genealogists are increasingly using shared and inherited DNA as another piece of evidence in determining and discerning family relationships.

People ask me all the time, which DNA test should I take? The answer depends on what you are looking for. I have some suggestions that will help you get the most for your money and help you get the answers that you are looking for. As I describe these tests, I’ll be sharing a few DNA basics to help you understand what you are getting before you settle on a specific test.

Autosomal DNA

Consumer Autosomal DNA tests (tests done on the 22 chromosome pairs that are not the sex chromosomes [X and Y] – and the most popular DNA tests on the market today) look at around 700,000 locations in a person’s DNA where the DNA code may vary. These locations are called single nucleotide polymorphisms, or SNPs for short. Testing companies compare information from newly taken DNA tests with others that are already in their databases. Information is generated that lists the people that share DNA and the amount of DNA that they share, listed in centimorgans (cM). A centimorgan is a measurement of the likelihood that DNA will recombine.[1] This number can be compared to a range of centimorgans found in known family relationships. In general, the higher the number, the closer the relationship. The sequence of nucleotides that make up a person’s DNA can be read like a sentence, but it doesn’t mean anything genealogically until it is compared with familial relationships and family history records.

So, if you are interested in learning more about your family members, ancestors, or your ethnicity, take an autosomal DNA (atDNA) test. There are 5 main testing companies that focus on atDNA. See the company comparison chart below. Each company is free to decide how to store and interpret your test results. This can be an important factor in deciding which test to take. Company policies are subject to change, but as of this writing, two of the companies, AncestryDNA, and 23andMe, do not allow raw data transfers of the DNA test results from other companies to be uploaded into their databases. Other testing companies allow test results to be transferred from another company, so if you think you’ll want to have your DNA results in more than one company database, it is best to test with Ancestry and 23andMe first. Raw data results from them may be transferred and uploaded to Family Tree DNA, where for a small fee, the company’s tools can be unlocked for $19. The same thing can be done with My Heritage, where $29 will give you access to matches and tools such as a chromosome browser. At this point in time, it is free to transfer to Living DNA, and they are in Beta testing with matches to be shown soon.

Company Comparisons

Why would you want to have your atDNA test results in multiple company’s databases? It’s all about making connections. Ancestry advertises heavily and has the most test results in its database…Family Tree DNA is best known for storing DNA samples for at least 20 years and having good tools to compare and understand data….23andMe is the only company that can legally share medical information, and it also has fantastic tools to help you see what sections of DNA you share with your relatives, My Heritage has a large European population in its database, and Living DNA has many testers from the UK. Some companies have databases that are predominantly filled with test results from certain parts of the world or specific ethnicities. And if you are searching for a match with a long, lost cousin who may know more about your ancestors than you currently do, they may have only had their test done by one company – and it’s only in that company’s database.

Y-DNA

If you are interested in learning more about your patrilineal line, or your father’s father’s father’s line, take a Y-DNA test or have a male in your family take one. The Y-chromosome is passed down basically unchanged for many generations. Test as many markers on the Y-chromosome as you can afford. The more markers, the higher the resolution the test will be, and the matches you receive will be closer in a genealogical timeframe. Family Tree DNA is the only company that currently sells Y-DNA tests.

Mitochondrial DNA

Finally, a third test says something about the genes that are passed only from women to their children. This type of test can provide unique DNA clues too. For example, if you are looking for information about your matrilineal line, or your mother’s mother’s mother’s genealogical line, take a mitochondrial DNA test. Information from this test can help you see if you have a common matrilineal ancestor with other testers, and it can show some of your matrilineal origins.

Informed Consent

A very important consideration in taking DNA tests yourself and in encouraging friends and family members to test is to contemplate the long-term implications of genetic testing. There is a possibility of uncovering unknown information, such as previously unknown relatives or learning that some family connections are not biological. The tester needs to know about these possibilities before agreeing to take a DNA test, and if you will be overseeing the test results, they need to sign an informed consent agreement. This will help you and your family members be aware of the positive and possible negative outcomes of DNA testing.

The potential of DNA research coupled with good genealogical work is one of the most exciting things in recent years to help break through many family brick walls. In the years to come, many more people will take DNA tests, which will help us all make more family connections, and more tools and techniques will be made available for use.

Continue to follow my articles here at Family Locket for more tips and guidance to incorporate your DNA into your family research.

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[1] https://isogg.org/wiki/CentiMorgan (accessed 7 February 2019)

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Andrea DuClos

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February 10, 2019 at 10:42 PM

Great information on DNA and the offerings of available testing companies. I look forward to hearing more from Robin in future articles. Thanks for adding DNA to your blog discussions.