Here at The DNA Geek, we want you to solve your DNA puzzles. Sometimes, that means research-for-hire, and sometimes it means giving you the information you need to help yourself.
That’s what the DNA Q&A series is all about! Have a question? Just ask! Think of this as a relationship advice column but for genetic genealogy rather than bad lovers.
Let’s get started with a few questions from “P.E.”, who contacted me via social media. P.E. asks:
I am an only child and my elders have all been long passed. Does DNA have any particular value to me?
Yes, it does! While it’s better to test your parents than yourself when it comes to autosomal DNA (atDNA), that’s not alway possible. In fact, it would also be better to test your grandparents than your parents, and your great grandparents than your grandparents. But few of us can do that, so we test the generations we’re able to.
Although you only inherited half of the atDNA of each parent, you still carry plenty of their DNA and will “match” relatives who are related to each of them. These matches are people who share DNA with you via a common ancestor.
In general, the more atDNA a match shares, the closer the relationship. Sure, it would be better if you could have tested your parents, because they are one generation closer to those relatives than you are, but you work with what you have.
There are other types of DNA test, as well: Y-chromosome DNA (Y-DNA) and mitochondrial DNA (mtDNA). As a chromosomal male, you have both, inherited from your father and mother, respectively. Y-DNA can only trace relatives on your direct patriline (father’s father’s father’s etc.), and mtDNA can only trace relatives on your direct matriline (mother’s mother’s mother’s etc.) On the other hand, these types of DNA have the advantage of not being “diluted” the way atDNA is. In other words, a Y-DNA test on you is almost as good as a Y-DNA test would have been on your father or grandfather.
How do I decide which DNA testing company is best for me?
That’s a good question, but perhaps a better one would be “Which one is best for me first?” Because the truth is, once you catch the DNA bug, you’ll want to be in more than one database!
The best place to start is with AncestryDNA. I say this for a few reasons. First, they have the largest database by far—more than 20 million people. And the larger the database, the more likely you are to find DNA relatives who can help your genealogy research.
Second, they have some great built-in tools for working with your DNA matches, and enthusiasts have created additional tools that you can install on your internet browser for free.
Finally, the smaller databases, like MyHeritage, will let you upload your AncestryDNA data file rather than having to pay for a whole new test. These sites may charge a small fee for a full suite of tools, but it’s cheaper than buying a second (or third) test. AncestryDNA does not accept uploads, though, so if you tested in one of the smaller databases first and then wanted to try AncestryDNA, you’d have to purchase an additional kit. You might as well just go there first!
How does DNA help me trace individuals related to me?
Your genealogy DNA company will “match” you to other customers who share DNA with you. With atDNA, the more DNA they share (measured in either percent or a unit called centimorgan), the closer the relationship generally is. The testing company will give you a rough estimate of the relationship to guide you.
Where can I obtain understandable guidance, once I get my results?
Believe it or not, one of the best places to get help with your DNA results is Facebook! There are dedicated groups for genetic genealogy in general, for each of the testing companies, for specific geographic regions and populations, for third-party tools … you name it! For example, I run a general DNA group called The DNA Roundtable, one dedicated to the What Are the Odds? tool at DNA Painter, and one for Louisiana Cajuns and Creoles. Group members enjoy sharing information and helping one another.
There are also blogs like this one, which are free, as well as practical books like Diahan Southard’s Your DNA Guide: The Book.
If you need one-on-one attention, you can also do a paid consultation with myself or another qualified genetic genealogist.
There are lots of options to choose from!
Have Questions About DNA?
Just ask in the comments! Your question may show up in a future column.
Disclaimer: All dating advice will be limited to tMRCA (time to most-recent-common-ancestor).
Many thanks to genealogist and graphics wiz Michelle Custer Bates for the title graphic!