I had this email recently from Pete of the Whitson YDNA Project:
Joel, I am terminal SNP R-BY97752. Do the large number of ‘private variants’ suggest that I may potentially have a whole mess of possible SNPs between my Y-111 terminal SNP of R-S23139 and the ‘BIG Y 700’ terminal SNP of R-BY97752 that have not been seen in other test to this date? If so, isn’t that a large number of possible SNPs?
This was a reasonable question. My short answer was yes, but I said I would give some more detail. Pete sent me a screen shot of his BigY Block Tree. I’ll insert my own version here:
I had to shrink the block tree down a bit to show everyone. Pete shows no matches. He does have a name who is Milos listed to the right. FTDNA’s matching formula is strange, because Pete should be more closely related to the two testers under BY62217 which is under Pete’s BY97752.
Pete at the Whitson Project
Pete is broadly under the U106 section of the Whitson project:
Pete has close STR matches to the other STR testers in the project. However, Tom and Dan have not taken the BigY test. They did take a single SNP test for R-S23139 which is higher up on the SNP Tree. One easy to understand site for SNPs is the SNP Tracker web site. My guess is that Pete’s BY97752 is about 2,000 years old. S23139 would be even older. Here is the overall map:
U106 is an Anglo-Saxon SNP. At this time, according to the map, Pete’s branch of Anglo-Saxons hadn’t made their way to England. Here is the SNP Tracker timeline:
For some reason, the SNP Tracker gives the same date for S23139 as it does for BY97752. This doesn’t make a lot of sense, but I guess they are saying that these four SNPs are all around the same date. The three matches under BY97752 are Pete and the two who are under BY62217 which is under BY97752.
Here is a closeup of Pete’s private Variants:
Let’s say that BY97752 is 1,600 years old. There is another SNP in there with it called FT136511. Let’s add those to Pete’s 21 Private Variants and get 23. When I divide 1,600 by 23, I get about 70 years. That means that these variants or SNPs are forming about every 70 years on average on Pete’s line.
The block tree acts as a very accurate family tree. However, this tree is very old right now. If Tom or Dan from the U106 Branch of the Whitson Project were to test for the BigY, that would bring their branch of humanity into the genealogical timeframe and start to name SNPs that are uniquely Whitson. To me, that is the goal of BigY testing. The other goal is to find one’s deep roots. In Pete’s case his roots were in Germany – perhaps fighting or joining with the Romans. In fact the other tester under BY62217 which is the parallel branch to the Whitson branch lists his background as German. So, if there was another Whitson U106 tester, the branch would end up looking similar to the BY62217 branch. Most of Pete’s Private Variants would then be subsumed into his new SNP in a blue box. One of those SNPs would be named as representative of the new group. Then Pete and the new tester would have a smaller number of their own private variants which would be averaged in the Block tree.
BigY and the Rule of Three
Bill Wood from the BigY Page on Facebook promotes the Rule of three. In my own words, that rule is to test yourself for deep roots information. That is what Pete did. Then test a relative – say 4th cousin or 6th cousin. That will get you more information. However, look at BY62217. The common ancestor between the two of the testers in that group is roughly 4 private variants away. So that could be roughly 280 years. Yet the date of their named SNP is still quite old as it formed probably not too long after BY97752. The third tester which is a close relative then names most or all of the remaining private variants and forces further branching and a newer terminal SNP.