Statistics for the I-M170 Y-haplogroup I-L38 (End of 2023)


The I-L38 tree is growing and new testers are constantly being added. In the past, the standard test for Y-DNA at FTDNA was the STR test, with 12, 25, 37, 67 and 111 markers, and the Y-haplogroup was and is only predicted with I-M170. Other suppliers also had and still have panels with a different number of markers, e.g. the PowerPlex® Y23 or the Y-STR panels from YSEQ. Even initially offered Y-STR tests that could be uploaded to FTDNA. With adequate Y-STRs and some experience, you can predict the Y-haplogroup a little deeper than with FTDNA (I-M170) and for a while it was common to verify this with single SNP tests or SNP packs. Nowadays you can choose the same procedure, but in my opinion it is more reasonable to buy an NGS (Next Generation Sequencing) test, which is now affordable. At FTDNA this is called Big Y700, with other providers you can do a WGS and upload the relevant data to
For my research, but also for the FigUre tree, I have collected our I-L38 cousins from all possible databases and want to show a few statistics here. Sometimes you have to add apples and oranges together, as it is not easy to summarise data with different levels of information, but you still get a small overview.

Source of Data

FTDNA has the largest database for Y tests, both for Y-STR tests and for NGS tests (Big Y 700 and Big Y 500), so most of the data is from there. In the tables of the numerous publicly accessible projects, you can search for the I-L38 kits using the predicted Y haplogroup I-M170 or the verified SNPs and the Y-STR markers and, with the experience I have been able to gather so far, classify them more or less specifically in the respective subgroups.
The Big Y block tree contains the tests in which the Y haplogroups are verified by SNPs. The majority of these are now Big Y tests.


At private testers can upload their NGS data. In addition to the BigY from FTDNA, it also contains uploaded tests from other providers, as well as tests from scientific studies in which living people were tested. Although data from ancient DNA samples are added to the database, they are not counted in these statistics.

More Data

  • Serbian DNA Project, Y-STR Data (PowerPlex® Y23)
  • Y-STR Data and low level Y-SNP Data from scientific studies that have not been uploaded to YFull.
  • YSEQ, Y-STR Data

Breakdown by subgroups

So far, I have found around 2000 tests with the Y haplogroup I-L38 in the various databases. On the one hand the NGS tests (e.g. Big Y) with verified terminal SNPs and on the other hand the Y-STR tests, in which the sub-branches were only predicted. I was unable to predict a subgroup in around 350 tests. Some of these are Y-STR tests, where a more precise categorisation by STR markers is not possible. Another part are tests that were verified as I-L38 by single SNP, but cannot be further predicted by Y-STR because the Y-STRs are not accessible (tester in no project). In total, there are about 17% that are not taken into account when categorising into subgroups.
For a simple overview, I have used the “main subgroups”, which we are still familiar with from the good old Y-STR grouping. Note that some of these form groups together. (S2606, FGC29656, Y13076)

560 tests were verified by NGS (Big Y and other NGS tests). This is an average of around 28% of the total tests. The proportion of NGS tests is highest in group S2488 and lowest in group BY1183. The following graph also shows the relationship between FTDNA-Big Y and other NGS.

Breakdown by Country of Origin

For all databases, it is possible to enter details for the earliest known paternal ancestor. This information is voluntary and is more or less filled in by the participants themselves. Unfortunately, the number of tests without information is very high at approx. 50%. In addition, there is a relatively high number of testers who cannot clearly assign their origin to a European country, so that there are numerous entries such as United Kingdom (instead of e.g. England, Wales) or United States and other American locations.
At this point, I have found and added this information to some kits by hand and research to the best of my knowledge and belief.

Link to the interactive graph

The majority of the Y-haplogroup I-L38 comes from England, Scotland and the rest of the United Kingdom and Ireland. This means that almost two thirds come from the islands and only around a third from mainland Europe. On the mainland, our Y-Haplogroup is most strongly represented in Germany, Switzerland and France.

I am a big fan of NGS tests, so I am very interested in the percentage of testers who have taken an NGS (like Big Y). That’s why there is not only a graph for the NGS tests per subgroup, but also for the NGS tests per country.

Link to the interactive graph

Another interesting illustration is the breakdown of the subgroups by country.

Link to the interactive graph


When creating the FigUre tree, I noticed that unfortunately the information for Country of Origin was missing in many tests, which made the tree look a bit sad, as there were many points with Unknown Origin. This was similar when compiling these statistics. Therefore I would like to ask all testers to enter their “Country of Origin” and if not already done to join the I-L38 Project at FamilytreeDNA.

4 thoughts on “Statistics for the I-M170 Y-haplogroup I-L38 (End of 2023)”

  1. Antonios, I believe a majority of those with the Country of Origin being the United States probably can’t identify an older ancestor in England. Five of these 117 have a “known” common ancestor who lived in America in 1715. They spoke English, attended Christian churches and are identified in Virginia Parish records, 1720-1760. We know our “older” ancestors were English; we just can’t identify any of them. To make matters worse, we are looking for someone who lived in England in the mid-to-late 17th century and belonged to signature Haplogroup I-BY172565 that “formed” around the year 1650. Obviously, the United States is not our real “County of Origin”; I’m sure this assignment is a real disappointment for others like me. Jim

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