Understanding Y-DNA Results – STR Markers

I’m still in the early stages of learning about genetic genealogy and have found much of the information very complex. There is quite a bit of jargon and several acronyms involved so I thought I’d write some posts in the hope of simplifying it … for both you and myself. This first post should help you interpret your Y-DNA results, if you’ve taken a test, or the results displayed in the project, if you haven’t taken a Y-DNA test yourself.

Males have a Y-chromosome which they inherit from their father. This can be used to trace a paternal line back for hundreds, or even thousands, of years. Females don’t have a Y-chromosome and so only men can take a Y-DNA test. Both men and women inherit mtDNA from their mothers and this can be used to trace maternal lines but that is beyond the scope of our Tickle DNA project.

STR Markers

Y-DNA tests examine markers on the Y chromosome, known as STRs (short tandem repeats). There are tests for different numbers of markers, such as Y-DNA12, Y-DNA25, Y-DNA37, Y-DNA67, Y-DNA111, and Big Y700, which tests 700 STRs. The recommended starting level for genealogy is Y-DNA37, which gives basic information about your predicted haplogroup and any matches found in the database at the 37-marker level. Y-DNA37 is good for showing whether you are related to other men with the same surname.

You can view the latest results at https://www.familytreedna.com/groups/tickle/results. The Classic Chart shows the results for each marker for everyone in the project who has tested. In the chart below you can see the names of the STR markers in the top line, eg: DTS393, DYS390, etc. The figure below each of them is the number of times that STR is repeated in the chromosome. These numbers form a haplotype, a sort of genetic ‘signature’ that can be compared to other results in the testing company’s database to find matches.

You’ll probably have many more matches at 12 markers than at 25 or 37. Matches at the lower levels are unlikely to be significant for your family history. I recommend that you switch off notifications for matches below 37. You can do this by clicking on Account Settings under your name at the top right of the FTDNA window, then selecting NOTICIFICATION PREFERENCES. Turn off notifications for Y-12 and Y-25 by moving the sliders to the left.

Mutations & Genetic Distance

Although Y-DNA is passed down relatively unchanged through the generations, it mutates often enough that different family lines will not match exactly.

The Colorized Chart, which is also available from the results page of the project, makes it easy to see these differences. For example, in the Tickle project Lancashire sub-group there are differences/mismatches in the STRs shown on the left, among others.

Genetic Distance for Y-DNA testing is the number of differences or mutations between two sets of results. This gives you an idea of how far back your common ancestor would have been.

At 12 or 25 markers you will commonly get matches with men who don’t share your surname, and it’s possible to get these ‘false matches’ at 37 markers. Testing more markers with Y67 and Y111 will eliminate most of these. As you test more markers you will normally get fewer and fewer matches but the ‘real’ matches will get closer and closer, while the ‘false’ ones get further away.

For men who share a surname and match at Y-DNA37 this is what genetic distance means:

0Very Tightly
A 37/37 match between two men who share a common surname (or variant) means they share a common male ancestor. Their relatedness is extremely close with the common ancestor predicted, 50% of the time, in five generations or less and over a 95% probability within eight generations.
1Tightly RelatedA 36/37 match between two men who share a common surname (or variant) indicates a close genealogical match. Your common ancestor is probably within 5 generations (although it could be as long as 14 generations). It’s most likely that they matched 24/25 or 25/25 on a previous Y-DNA test, and the mismatch will be found within DYS576,, DYS570, or CDY.
2RelatedA 35/37 match between two men who share a common surname (or variant) means they share a common male ancestor. It is most likely that you matched exactly or closely on previous Y-DNA tests, and the mismatch is within DYS439 or DYS385, DYS389i, 389ii, DYS458, DYS459, DYS449, DYS464, DYS576, DYS570, or CDY.
3RelatedA 34/37 match between two men who share a common surname (or variant) means they share a common male ancestor. It is most likely that they matched exactly or closely on previous Y-DNA tests, and the mismatch is within DYS439 or DYS385, DYS389i, 389ii, DYS458, DYS459, DYS449, DYS464, DYS576, DYS570, or CDY.
4Probably RelatedA 33/37 match between two men who share a common surname (or variant) means they may share a common male ancestor. This relationship should be confirmed with additional testing. The only way to confirm the relationship is to test additional family lines and to find where the mutations took place. By testing additional family lines, you can find the person in between. This ‘in betweener’ is essential for you to find.


FTDNATiP™ (FamilyTreeDNA’s Time Predictor) is a program that predicts the time to the most recent common ancestor for two men, based on their Y-chromosome STR matching and STR mutation rates. Some STRs mutate more frequently than others and so it modifies the genetic distance to take this into account. It will give you a percentage probability that you have a common ancestor in 4, 8, 12 generations etc. To calculate roughly how long ago this is likely to be multiply the number of generations by 25. So a common ancestor within 8 generations would be within the last 200 years, ie: since 1820. You may well be able to find a paper trail to back up this connection.

To use the FTDNA TIP tool

  1. Sign in to your FTDNA account
  2. On your dashboard, select Matches in the Y-DNA section.
  3. On Y-DNA – Matches, click on the orange TiP icon next to a match’s name (see the image above) to run the report for that match.

Lancashire Results

The diagram below shows the matches and the genetic distance for those project members in the Lancashire Tickles sub-group. I have used letters to preserve members’ anonymity. You’ll find the kit numbers each letter represents on the right so, if you are a project member in the Sub-Group A, you can identify where you are on this diagram.

AKit No: 742884DKit No: BP12273
BKit No: 934154 EKit No: MI20708
CKit No: BP12217FKit No: M133208

All members of the sub-group are probably related to each other but it requires further testing of distant relatives to try to find the connections and where the lines split.

German Tickles

There are currently only two Y-DNA matches within the project for those Tickles with German ancestry, although there is a close match with another Tickle who has not yet chosen to participate in the project. Here are the links and genetic distances.

Kit No: B638491
BKit No: 933244
CNot yet a project member.

Another two Tickle males who have taken a Y-DNA test do not as yet have any matches. I’d love to find them some others in their line! If you are a man with the Tickle, Tickell name or another variant, do please consider joining the project. You can contact me to find out more.

I hope you have found this useful. In my next post I’ll explain what haplogroups are and where the Tickles and Tickells fit into the universal Y-chromosome tree.

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