DNA Testing Guide
There are many reasons to do a DNA test for genealogy, as well as many limitations with ever-evolving results. Results can give you a sense of origins, sometimes to a small region or historic period (e.g. “Early Connecticut Settlers”, “Southwest Mayo in Connacht, Ireland”). They also come with matches of people who share your DNA in varying and significant degrees, which can offer a means to enrich your family tree, break through “brick walls”, as well as find helpful collaborators.
Below is a summary of the types of tests available, the companies that offer them, and some caveats to consider. And if you’re interested in doing a DNA test (or better yet, getting your parents to take one) but would rather jump straight down to what I recommend, you can skip the details by going here.
Three kinds of available tests
1) Autosomal DNA - This test looks at a general sampling of your genome and where the “ethnicity” percentages are derived from. This is the most common type of DNA test to yield useful matches in helping with genealogical research that encompasses the last 500 years, as well as give you a fun ever-changing (due to database adjustments) pie chart of your ethnicities.
2) Mitochondrial DNA - This test looks at the DNA inherited from your mother’s mother’s mother’s (etc) line. It will take you back to one of the relatively small number of “mothers” in global prehistory. It’s interesting, but I have yet to see how it helps in more recent genealogy research. If a relative who descends from the same matrilineal line has taken the test and you know those results, there’s no need to spend money to take this test. In rare cases a high-level match might reveal who a great great etc grandmother is. It also could confirm that a DNA match comes from the same maternal line.
3) Y-DNA - This test only pertains to men and will reveal the father’s father’s father’s (etc) line. If you’re a woman with a living brother, father, paternal uncle, or nephew you can potentially learn a fair amount about your paternal line if one of them takes the test. This could be especially useful if you have reason to believe a particular line had a non-paternal event. That is, that the presumed father of an ancestor was passed off as biological when that wasn’t the case. It might also be useful if you know the surname in question was changed for some reason. Otherwise, a Y-DNA test will illuminate a deeper history, including the general migration of the deep ancestry of your paternal line.
I personally think DNA tests are an incredible tool for aiding in genealogy research. So I highly suggest taking a DNA test (or 2 or 3;-)—with a few caveats:
1) You might get some surprises you aren’t expecting. These could be relatives you didn’t know about, or even a whole different lineage than the one you were told about growing up. So if you don’t think you can handle potential dramas like that, maybe don’t test.
2) You might get results that seem kind of dull or unhelpful. So it’s best to go in with an attitude of curiosity and patience. New matches come online all the time, and a helpful match just might not be there yet. Also, ethnic percentages and technology are always changing. What seems like a soup of matches might turn into strong and provable ancestry lines as technology advances.
3) You might get an overwhelming number of matches. If part of your ancestry stems from endogamous groups (populations with generations of intermarriage) or isolated regional groups, there will be an inordinate number of matches that show as closer-than-they-actually-are relatives. It’s easy to get overwhelmed, but depending on what the goals are, it’s possible to solve familial mysteries and flesh out the family tree. It will all depend on the quality of your matches—as well as your level of patience.
4) Privacy concerns. I totally get why it’s nervous-making to put a DNA sample out there. Although companies say they anonymize the data and don’t sell personal details, it’s reasonable to be protective. One way to minimize access to your information is to submit your DNA without identifying information. You can set up an account with a separate email and non-identifying username. And while perhaps cynical, it’s worth stating: If someone really wants to find private details about you, they can and they will. With basic internet skills, a determined person could probably track someone down. As for DNA, it’s already technically possible to gather it from the air (see NYT article from 15 May 2023: "Your DNA Can Now Be Pulled from Thin Air"). But as always, taking a DNA test comes down to one’s comfort level balanced with the potential benefit.
The Major DNA Companies
Ancestry is the go-to place for autosomal testing because it has a huge database of users with lots of robust trees. If there is hope of finding matches who have done research relevant to your family history, you'd likely find it here. It's worth noting that Ancestry charges separately to subscribe to their genealogy platform, so once you start finding matches with trees, you may find yourself wanting a subscription to gain full access. Be sure to keep an eye out for their deep discounts on DNA kits, offered throughout the year.
This is the only company where males can get a Y-chromosome test, which traces the direct paternal line. They also offer mitochondrial (matrilineal) and autosomal testing. FTDNA has long been considered the most focused company for Jewish genealogy research — they identify multiple Jewish ethnicities and partner with JewishGEN, an excellent Jewish genealogy resource worth knowing about. That said, I would not choose FTDNA in lieu of Ancestry, as only a small minority of users put up trees. Basic access is free, though full access to all tools requires a nominal fee.
MyHeritage is the number one DNA testing platform in Europe and is available in more than 40 languages — which means its database skews meaningfully international compared to Ancestry. If you're hoping to find matches with relatives in Europe, Latin America, or other parts of the world, this is where you're most likely to find them. They also offer some superior comparison tools, most accessible with a subscription.
23andMe evolved from, and remains more dominant in, the health space rather than the genealogy space. Most of their submitters don't include trees, so match quality for genealogy purposes can be limited. That said, they do have some useful tools, and if you end up with a fair number of matches here it can help you get a more detailed look at particular branches of your tree. A notable bonus: 23andMe automatically includes broad mitochondrial haplogroup results for everyone, and Y-DNA haplogroup results for males — a nice extra if you're curious about deep ancestry. One caveat worth noting: the company filed for bankruptcy in 2025 and was subsequently acquired by a nonprofit created by the original founder. There were privacy concerns during this transition, and some still advise caution — worth factoring into your decision.
A NOTE ON UPLOADING RESULTS BETWEEN COMPANIES
Depending on which company you test with and when, it may be possible to download your raw DNA data and upload it to another company — a useful way to expand your pool of matches without purchasing multiple tests. However, transfer compatibility between companies changes frequently, and what works today may not work tomorrow. Before counting on this option, check each company's website directly for their current upload policies.
A NOTE ON ETHNICITIES
All companies will offer a slightly different version of ethnicity results, which can be interesting. Sometimes the difference is not so slight, which is a reminder to take them with some grains of salt. They derive their definitions based on their databases. Also, with history and migration of peoples, ethnicities can be loosely defined.
Ethnic groups you’re assigned to will be updated regularly as their databases grow. For example, MyHeritage is aiming to really define and narrow origins to smaller communities (e.g. not just broad Ashkenazi Jewish, but, say, a region or village area of Lithuania). As these results get more refined and more people add to the database, these tests will become much more helpful in genealogy research.
Recommendation summary:
1) Order an AncestryDNA test since it has the largest database and the most trees.
2) Purchase a MyHeritage DNA test if you're curious about seeing a potentially more detailed ethnicity chart and/or discovering more "cousin" matches around the world.
3) For yet more insight you can purchase a 23andMe test as well. Since they include basic maternal haplogroup (for everyone) and paternal haplogroup (for males) as part of their standard test, this is a nice bonus if you're curious about deep ancestry. Note, however, that 23andMe went through bankruptcy in 2025 — see the company notes above for context before deciding.
4) If you hope to understand more about your paternal line AND you are male, or have a brother, father, uncle, or nephew on that line who is willing to test, order a Y-chromosome test at FTDNA. (I suggest starting with the basic 37 marker test — you can always upgrade if results warrant it.)
5) Order a mitochondrial test at FTDNA only if you have a curiosity about your deep matrilineal roots, or you have no other means of tracing your matrilineal line (such as in cases of adoption).