Recap: Part 1 discussed why to do a DNA test. Part 2 about how and where to test. Part 3 delved who to test and the two other genealogical DNA tests. Now let’s now talk about the best part of the test.
Most people test their DNA either because everyone is doing it (or got it as a a gift), or to find out their ethnicity. Most Jews are disappointed since it tells them what they already knew — they’re 95-99% Ashkenazi Jewish.
But the most useful part of the DNA results are not the ethnicity estimates. Rather, it’s the list of thousands of relatives who match your DNA, both near and far (genetically speaking).
Depending on the company, you can get between 1,500 and 200,000 matches, and they’re all your cousins. Understand that you will almost never go through all those names, nor should you try. You’ll be focusing on those who share the most DNA with you, which are those closest to you, at the top of your list.
So if your parent, sibling or child tested in that company, they’ll be at the top of your list. Otherwise, it will likely be first through fourth cousins, whether you know them or not. The rest are distant cousins (fifth-eighth).
But what do you do with all those matches? In the big picture, they are family, and can help you go back several generations (sometimes more if you’re lucky.) How specifically can they help?
Depending on the testing company, the tester may have attached a family tree, which can help you find common ancestors.
Three of the five companies allow for attached trees, and that includes the largest testing company, Ancestry (but not 23andMe.) Sadly, many people don’t post their trees, and if they do, don’t assume they’re completely accurate. Use them as tips to do further research. You should post your family tree, to help potential cousins find you.
Your genetic cousins (known and unknown) may have documents, photos or family stories of your ancestors. The first step is to see how you’re related, then ask if they’re willing to share items that will help both of you (re)connect your branches lost over time.
You can use known genetic cousins’ DNA to identify unknown matches and hopefully go back several more generations. This requires a bit of a steeper learning curve, but is well worth it.
All companies allow you to send a message to your matches, but be aware that it may take a while to get a response, and a number never respond. But it’s worth a try.
Each company names and displays the match list a little differently, but all will show you at least:
Matches’ names. They may be real or pseudonyms.
Amount of shared DNA. This will be either a percentage or a number in centiMorgans or cM.
Predicted relationship: range of possible relationships, based on the amount of shared DNA.
Example: On Ancestry, one of my matches is a known cousin: Rebecca Myerson (not her real name), second to third cousin, 212 cM/3% shared DNA, with a public tree.
At 212 centiMorgans, Ancestry is guessing that Rebecca is somewhere in the second to third cousin range, which could include a second cousin, 1C2R (first cousin twice removed), half 2C, 2C1R, half 1C1R — and other possibilities.
Rebecca is actually my second cousin, so the guess was correct. Se has a public family tree, allowing me to confirm our common ancestors, which are our great-grand-parents.
There are a number of tools each company gives you. One of them is called shared matches. It allows you to choose one of your matches and shows all the matches both of you have in common. It could be just a few, or thousands. This is helpful for non-Jews, but because of endogamy (marriage between cousins for many generations), it can be less helpful.
Nonetheless, it can help narrow down which branch an unknown match might be part of, by looking at who else the two of you share DNA with.
There are many videos and webinars out there in InternetLand to help you learn and practice how to use DNA effectively, regardless of prior experience. FamilyTree Fanatics, Legacy Family Tree Webinars and YouTube are some of the resources. All have tutorials and many are free.
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