Tuesday, September 22, 2015

Tested 67 ySTR Markers? Now What?

You have tested 67 ySTR (short tandem repeats) markers and you still want to learn more. What's a guy to do? If you have several closely bunched matches at that level, you may want to upgrade your test to 111 markers to see if that will sort your matches out a bit. On the other hand you may be ready to start exploring your SNP (single nucleotide polymorphic) trail down from prehistory to you.

If you have tested at FTDNA, you already have been given an estimate of your haplogroup (ancient clan). 

In this example the suggested haplogroup is R-M269 

One way to look at your haplogroup is as an exit number along the great SNP inter-eon freeway down which your genome has been traveling for thousands of generations. In this case your ancestor had a permanent change (SNP) in his genetic migration at exit R-M269. Since that point all of his male descendants have continued to carry that same SNP to document their journey down to you.

However, this SNP is probably carried by millions of men living today. If you want to document your migration path more precisely, you will have to become a SNP chaser.

If you are a novice ySNP chaser, you will have to reorient your thinking a bit. When you read the results of a 37 marker, 67 marker or 111 marker test, you are used to seeing the number of STRs that occur at given locations along your genome. Generally these are numbers like 10 or 28. These results were used by the lab to group you with other men who have identical results on most of the markers tested. It takes identical results at a group of locations (e.g. 37 or 67) considered simultaneously to identify men who may be closely related in genealogical times. Generally the more exact ySTR matches two men share, the closer they are to their common paternal ancestor. The process is somewhat like a census conducted by going to 37 or 67 houses (predefined genetic locations) and counting number of ySTRs that reside there. It is a census of STRs that live there currently.

With ySNPs we are documenting a journey that is recorded in a diary of all the branching points that have occurred in the past. It is like driving from coast to coast and listing in sequential order each of the interstate exits you took. In the example above the most recent branching point the lab was able to estimate was exit (SNP) R-M269 which first showed up in the genomes of that man's ancestors many thousands of years ago.

If you would like to get some idea of where other important branching points of your genome may have occurred without spending more money on testing here is one technique:

Click on "Advance Matches" shown in the illustration above.

On the following screen select "Y-DNA67" and then click on "Run Report":

A results page similar to the one shown below will appear. 

This page has been truncated for privacy of  the men reported.
In all likelihood the SNP trails of all of these men have been identical down to the last few millennia, they show a wide variety of results in the "YDNA Haplogroup" column on the left. These differences reflect the depths of testing these men have gone through. Some of them have had no specific SNP testing at all and are predicted to be M269. Others had had some level of SNP testing completed and have been advanced to exit R-L21 -- the most common male haplogroup along the Atlantic coast of Europe. Some have taken the BIG Y test and been assigned the more precise haplogroup R-S1026. In this example it is highly likely that all of these men belong to this later classification but only testing would verify that conclusion. The relatively close 67 ySTR results (right column above) allow me to make that prediction.  

At present SNP chasing is really in its infancy. A vast majority of the SNPs we know today have been discovered in the last two years. We are still working to find the exact location and sequence for many of them. In some ways our knowledge today would be like getting a SNP passport with several dozen stamps on it but in random order. We know that our genomes passed through all those points but are still trying to decipher in what sequence that journey occurred. As more men are tested and we can document where they exited the main SNP trail, we can refine our chronology for all of us.

The above exercise should give some sense of direction for further SNP chasing research to trace the path of your ancestors down into the genealogical age. At present R-S1026 is the most recent checkpoint FTDNA has added to its published SNP Tree. Most estimates are that R-S1026 has been around for about 3,500 years. The each of the men in the above chart who have confirmed their R-S1026 status through BIG Y testing now have three dozen or so SNPs more recent than R-S1026 stamped on their passports. Some of those SNPs are shared with others and a few of them are unique.

In my next post I will discuss three separate testing strategies for exploring your SNP trail.


  1. I'm a snp chaser on behalf of my dad, so thanks for your post and I look forward to the series. He has no matches at 37 markers and we are currently confirmed as R-M312. I ordered him the new backbone pack so hopefully taht will shake us further down the phylotree.

  2. Thanks for your comment. Those of you exited the main R1b SNP highway prior to R-L21 don't have as many matches. I don't know whether this is because more of those who have tested are from the Atlantic coast of Europe and those who migrated from there to North America and other British colonies. I don't know if long term we will see a different pattern of matches.

    In response to your point about no matches at 37 markers, as I'm sure you are aware, the prevailing wisdom is that you will have fewer and fewer matches as you test more and more markers. That is generally true. However, STRs mutate at random as far as we now know. There can be a convergence as more markers are tested. I have a 6th cousin -- once removed who mismatches with me on marker #1 and again on marker #18. This sometimes prevents us from showing up as close matches. However, we have NO mismatches from marker #19 to marker #111. We end up as matching on 109 of 111 ySTR markers.