Today is National DNA Day. April 25th commemorates the successful completion of the Human Genome Project in 2003 and the discovery of DNA’s double helix in 1953. It’s a day given over to learning more about genetics and genomics. For genealogy it’s also an opportunity to pick up some great deals on the various DNA kits available.

You can find a list of the various sales available from the various genetic genealogy providers here

https://nationaldnaday.com/dna-day-sales/

But if you’re not already familiar with DNA testing for genealogy what do you need to know? What are the differences between the various tests?

The most common test (and the most affordable) available from most of the providers is the Autosomal test, otherwise known as the Family Finder test. It tests back along both the male and female line. It can also provide clues to the ethnic background of the tester. However, this should always be taken with a certain amount of caution. There are any number of variables which can skew the test and sometimes the different providers will provide a tester with very different results. Autosomal tests also have a limited range, only been accurate within seven generations.

Ethnic breakdown from Family Tree DNA autosomal test

What makes autosomal testing so useful for genealogy however is that it can provide you with direct matches to potential cousins. This can be particularly helpful for getting beyond those pesky brick walls if you can connect to someone who might have been able to progress further in their own research. If you want to narrow your results to a particular branch of your family then a helpful strategy is to test a relative connected to you on that branch. For example if you wanted to find more connections on your paternal line, then ask a first cousin or uncle or aunt, to take the test also. You can then compare any matches in common. Similar can be done with second cousins for information on great grandparents and so on.

If you are curious about the origin of your surname or looking to go back further along the male line, then the test to take is the Y chromosome test. The Y chromosome is passed down along the paternal line from father to son. As such only men can take it because women don’t inherit that piece of DNA. This test can go back much further, roughly 1000 years, hence why it is so useful for tracing the origin of a surname. From my own experience though, it might not tell you a whole lot if you have a common surname like Ryan. Another limitation is that the test won’t necessarily help you find close cousins.

For those looking to trace the origin of their maternal line, they can take the mitochondrial DNA test. Mitochondrial DNA is inherited along the female line for both men and women. It also doesn’t mutate at the same rate as other types of DNA and can be traced back much further. However, because women often change their surname when they marry, it has limitations if you are trying to connect with a specific individual. However, one interesting use of mitochondrial testing in recent years was the identification of the remains of executed 1916 leader, Thomas Kent. By taking a sample of mitochondrial DNA from his surviving nieces, they were able to confirm his identity.

If you are looking for more information on DNA testing then the video below should be of help

There are also plenty of other great articles and blogs out there. You can also find some excellent videos on personal experiences with DNA testing for genealogy on YouTube, courtesy of Genetic Genealogy Ireland.