DNA - Where do I test?


I’ve had some questions this week about DNA testing. Way back in February when I wrote What's the Plan? I emphasized the importance of starting your research with a question. It’s no different with DNA.


Why do you want to test?

What is the problem you are trying to solve?

Who do you need to test?


One of the things I hear constantly is that people are overwhelmed by their results. The next comment relates to their matches who do not have a tree, or really any information about their ancestry, and when you attempt to contact them, they don’t respond. Think about the advertisements you see on TV for DNA testing…what do they promote? They focus on ethnicity. I thought I was Scottish and but my DNA test told me that I was German. Many of these people have never considered doing genealogical research and probably don’t know much about their family. As genealogists we do know something about our family, and the ethnicity results can sometimes be frustrating. To quote Judy Russell, The Legal Genealogist, the ethnicity estimates “just aren’t soup.” As genealogists, we’re more interested in the cousin matches.


I spent years trying to figure out why I should test, and once I did, what to do with the results. I first tested in 2009 with 23&Me and I did it for medical reasons, not genealogy. I did get a list of matches, none of whom I recognized. 23&Me has gone through some major changes since I tested, and the medical results I got (which were extensive and pretty accurate) were removed. They stopped the medical portion of their testing as they worked with the FDA to get approvals. Some of the results are now available again. Since I usually write about health history in November I’ll put off the health discussion for now. (Thanksgiving Day has been designated as Family Health History Day by the Surgeon General since 2004.) I've now tested, or moved my results to all of the major DNA companies.

Jack Moughty and Pat Moughty

You need to begin by defining the problem you are trying to solve and creating your question. In 1992 when I first got started in genealogy, I met Jack Moughty in Ireland. Since Jack and my father-in-law, Pat Moughty could have been twins I was pretty sure there was a relationship, but the records didn't go back far enough for me to prove it with traditional research. My question was: Are Brian Moughty (my husband, and the son of Pat Moughty) and Jack Moughty related? Both are males with the same surname, so a Y-DNA test would likely answer that question. Only males carry the Y chromosome and it is passed with very little change from father to son. So it should show if Brian and Jack share a common ancestor. If you are trying to solve a male descendant issue within a specific surname, or possibly an adoption issue for a male, you’ll want to look at Y-DNA testing, and you have one choice; FamilyTree DNA. Although there is only one company, there is still a choice to determine how many markers to test. Depending on how common your surname, you may want to start with a 67 marker test. Moughty is very unusual, so I started with 37 markers.


If your problem relates to your female line, then mtDNA (mitochondrial DNA) would be the appropriate test and again, it is only available through FamilyTree DNA. Both males and females inherit mitochondrial DNA from their mother, but only the female can pass it on. Unlike the Y-DNA test, the mtDNA test isn't as easy to interpret as the surname changes with each generation. I don't recommend that you do this test unless you have a specific problem you are trying to solve. Here's an interesting blog from Judy Russell (The Legal Genealogist) that gives you an idea of why this test can be confusing.


In the case of both of these tests, you’re not likely to just take the test and see what’s out there. Brian and Jack, for example are the only two matches on their Y-DNA test with a distance of 0 or 1 (number of mutations) and they are the only Moughtys. If only Brian had tested I’d still be sitting here waiting for some kind of a match. Now if you have a very common surname, you may have the opposite problem of too many matches. In that case, you should look at Surname or Locality projects at FamilyTree DNA. They can help better isolate which branch of a surname you are likely related to. If you are looking for unknown parentage of a male, a group of matches with a particular surname might give you a hint.


When I did my mtDNA test, I wasn’t particularly trying to solve a problem, but rather trying to learn about mtDNA. It’s an expensive test, but I decided to go for the full sequence matching. My haplogroup is H1 (the most common). I currently have about 450 matches but only 1 has a genetic distance of 0. That could still be outside of the timeframe for genealogical records (especially with the Irish). According to FamilyTree DNA, a perfect match (genetic distance of 0) has only a 50% chance of being within the past 5 generations and a 95% chance of being within 22 generations (about 550 years). I have my female line back 5 generations to Ireland (likely Ulster, but no specific location) however the interesting thing with my matches is that they are primarily Scandinavian. But like Y-DNA, if you have a specific problem, trying to prove that a specific woman is related in your mother’s line and you can find a descendant in one or more lines, this test might be the answer. Here’s a link to an article by Debbie Parker Wayne (co-author of Genetic Genealogy in Practice) that explains mtDNA patterns. One thing to remember is that mothers pass their mtDNA to both sons and daughters, however, only daughters can pass it on. If you identify a male descendant on a matriarchal line, you may be able to test him.


Well, if Y-DNA addresses the direct paternal line and mtDNA addresses the direct female line what about everyone in the middle? That’s where atDNA or autosomal DNA comes in. Here your choices get considerably more broad. Next week, I’ll address the companies providing atDNA testing.


Happy Hunting!


If you're thinking of a DNA test for yourself or to have them available for potential cousins, check out the Promotions page for the current summer sales. FamilyTree DNA currently has a sale on both Y-DNA and mtDNA kits (as well as FamilyFinder).


I've also updated the DNA Links and Resources Page.


Registration is now open for the 2020 Ireland Research Trips.




FamilyTree DNA Summer Sale


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