Saturday, August 26, 2017

What do I do with my Y-DNA results?

I ordered a 37-marker Y-DNA test for my brother in 2005 to see if we could extend the Thompson line with DNA. Let's examine what to do when you take a Y-DNA test.

When you first order the test, you will be given a kit number and password. You will use this to access your results online. But it is not obvious what to do when you get your results. You will see this section on your account page:

What do I do with all of that?  Where are my results, and what do I do with them?  Let's first click on the Y-STR Results (the 8th item above).

What does the term Y-STR mean?  The STR test is the first Y-DNA test that you order at Family Tree DNA. STR stands for Short Tandem Repeat. A Short Tandem Repeat means that a short series of bases (nucleotides) is repeated side-by-side several times, something like a hiccup.

Here's an STR example: AGATAGATAGATAGATAGATAGATAGATAGAT. In this example, the sequence "AGAT" is repeated 8 times. There are many known locations on the Y-chromosome where these Short Tandem Repeats occur. Each of these locations is identified by a marker. The Thompson DNA test was a 37-marker test, so Family Tree DNA examined 37 locations on the Y-chromosome and reported the number of repeats. The first location was identified with the marker DYS393 which is DNA Y-chromosome Segment 393. At this marker the number of repeats was counted and reported--my brother had 13 Short Tandem Repeats at the location DYS393. Here are the complete results:

Family Tree DNA Y-DNA results

If that's all we got, the results would be useless. The entire purpose of DNA testing is to see who matches you. So the good news is that you don't need to understand or remember any of the information about STRs to use Y-DNA. You need to see who matches you, find out exactly how they match, compare family trees, and find additional people to do DNA testing to prove your theories.
Family Tree DNA has a database that finds matches for you. We will now look at the Matches icon in the first image above. This is how the results appear today:
Family Tree DNA Y-STR matches

You can see by the Match Date column that in 2005 my brother had only one match. That 2005 match is at the bottom of the list and is a descendant of Augustus M Thompson. This man is not an exact match--we know that because the Genetic Distance Column says that he has a genetic distance of 4. This means that on his 37-marker results he is mismatching my brother by 4 numbers. Again, that's not very useful unless we know which markers he is matching and which ones he isn't. For that, the first place you will turn is to your surname project because all of the results will be displayed there. If your match has not joined your surname project you will want to contact him by email.
The links that appear below each name will provide a way to contact the person, view his family tree if he has submitted one, and more.

We will examine various other issues (like why are there all those other surnames on the list like Akins, Barton, Brown, . . . ?) in subsequent blog posts, but for the next one let's head to the surname project to see if we can make sense of all of this. See Surname Projects: Examining my first Y-DNA match.

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