A Different Look at the I2 Butler/Whitson BigY Results

In my previous Blog, I set out to look at the finalized results of my brother-in-law’s BigY test. While doing that, I saw that a Whitson in the I2 section of the Whitson/Butler Project had also taken a BigY Test. That test apparently helped to place a lot of my brother-in-law’s previous Private Variants onto the YDNA Tree. Here is a summary of the overall Whitson Project:

The part that I am looking at in this Blog is the green area. This is on the YDNA tree in the general area of I2. Those who have taken the BigY test are in green. My brother-in-law is the next to the last tester on the list and my father-in-law is the last. Batt, Butler tester with James Butler as ancestor and my father-in-law Richard, had the older BigY500 tests. The new Whitson tester who doesn’t show an ancestor and my brother-in-law had the new BigY 700 tests.

The BigY Block Tree for Whitson/Butler at I2

Here is the Block Tree:

The Butlers are under I-Y128364. Batt has Whitson ancestry. that means that I-BY115420 is the Whitson side. Above this is a large Block of SNPs from position 7 to position 45 (not shown) collectively named for one of the SNPs in the Block: I-Y128591. The Block tree is from my brother-in-law Ken’s perspective, so he is not shown but is in the left column under I-FT241245. Because the older tests of BigY 500 did not cover a lot of the SNPs, the two new testers (one Butler and one Whitson) have greatly helped to improve the tree. However, I think that the tree could be better. I will likely discuss that later in the Blog.

The Different Look

Here is the different look from FTDNA. I’ll start with Ken. This just focuses on the individual, where the Block tree represents 5 testers. Here are the headings for the tree:

The detail will be in the five categories of tested SNPs.

There is no need to go too far up this tree. As I mentioned above, I-Y128591 has 39 SNPs in it. This could represent about 3900 years. I-Y128364 represents the Butler with the James Butler ancestor. I-BY115420 is the Whitson group. Ken only has two colors of the dots representing ‘tested positive’ or ‘presumed negative’. I would think that he should have some yellow dots for ‘presumed positive’. For example, Ken should be presumed positive for BY48499 under A427, then he should be presumed positive for FGC70597, etc.

Here are Ken’s results for BY48499:

This shows four out of five runs came up with a mutation at this location.

My Father-In-Law’s Version of the Tree

This view is pretty much the same except that, as he had the older BigY 500 test, he has more gray dots (which I believe should be yellow dots).

Tester with James Butler Ancestor

These results introduce a few more colored dots. FT241245 has a blue dot for downstream. He also has a red dot for S23897. That confirms that he tested negative for this SNP and was not just presumed negative. Again, I believe that all the gray dots above the highlighted row should be yellow dots.

New Whitson Tester

Here I highlighted a SNP with a red shopping basket. It is noted that this SNP is part of a SNP Pack.


I would expect to see more gray dots for Batt’s BigY 500 test:

Back to Private Variants

I spend a lot of time on Private Variants as they are on the cutting edge of the BigY tests. If these are really private variants, then they should describe a future branch of the tree. If they are not, then they should be describing an upstream branch of the YDNA tree.

Ken and His Dad

Due to the closeness of the relationship, Ken’s dad should not have any SNPs that Ken does not have. Richard has no Private Variants, but he also took a less comprehensive test. As these SNPs form about every 100 years on average, it would be rare also for Ken to have Private Variants. Yet he has three:

I have Ken’s Private Variants (PVs) in yellow above. These positions were not tested for in his father, but if they were, he would most likely test positive for them. The next to test is Eng Butler or the Butler with James as his ancestor. I have that he has a ? by his results for 17140468:

Batt has the same ambiguous results and Whitson has a definite no. That means that we don’t know if Ken’s ‘Private Variants’ should show up under FT241245 or Y128364:

Ken’s PVs probably would not show up under Y128591 as Whitson tested negative for these PVs.

James Butler Ancestor Private Variants

The tester with James Butler as an ancestor has these Private Variants:

If we can trust these are truly Private Variants, then we can say that they define the James Butler Line down to the present day tester.

Here, Ken tested negative for these two positions. So the two Private Variants for the James Butler ancestor are valid. There may be other positions that were not tested for under the BigY 500 test that could be private variants also.

Whitson Private Variants

These are from the newest tester in the group:

Whitson has three Private Variants. I’ll check Whitson’s closest match who is Batt. Batt is actually negative for 12984909:

The other two positions are unclear:

That means that it is possible that the second two positions could actually be SNPs for Batt and Whitson under BY115420.

Batt Private Variants

Batt has two PVs:

My guess is that these two should be valid. Again, I’ll check Batt’s closest match who is Whitson:

Whitson does not have the first position.

Whitson has a clear ‘no’ for 19550845 also. This means that Batt has two unambiguous Private Variants.

Common Ancestor Dating

This is easier to see in the Block Tree view:


The places where the common ancestors are dated are in the ewhite space btween the SNPs. The common ancestor between Butler and Whitson is in the white space where the second arrow is. The common ancestor between the two Butler families is in the white space where the first arrow is.

Common Butler Ancestor

In order to get to the date for the Butler ancestor we need to assume a number of years per SNPs or Private Variant. I will use 100 as a round figure. I know that Ken has three private variants, so I will say that he shares 1.5 private variants with his father. That is assuming that FTDNA is right with the analysis. It is also possible that Ken actually shares his Private Variant with the other Butler Branch. That would put those SNPs in a Block under Y128364.

I’ll add those 1.5 private variants to the the two SNPs under FT241245 to get 3.5 SNPs. Then I’ll average those with the other Butler’s two Private Variants to get 2.75. Based on the assumption of 100 years per SNP, that would results in a common ancestor for the two Butler Lines of 275 years ago or the year 1745. That sounds pretty recent.

Common Butler/Whitson Ancestor

There are many more SNPs on the Whitson side compared to the Butler side. This means that it is possible that the Whitson SNPs came about more often than the Butler SNPs. However, the end point has to be the same for the common ancestor for these two groups. that is where the second red arrow is above. Average 2.75 with 6 to get 4.375 or 438 years. That puts the common ancestor for Butler and Whitson at the year 1582. If I come back down on the Butler side and add 100 years for Y128364, I get 1682 compared to the 1745 I previously had.

I used the 1682 date above because it was based on averaging more SNPs. For the second Butler Line, that means that a SNP was formed about once every 130 years assuming that tester was born around 1940. Also, that tester may actually find more Private Variants if the test was upgraded to BigY 700. If we use the present date, then there would be a SNP every 170 years.

On the Whitson side, there were 6 SNPs in about 440 years to present. That is a new SNP every 73 years.

Summary and Conclusions

  • I took a look at 5 BigY tests from the point of view of their individual Y-DNA Haplotrees. This look gives some extra imformation on the testing results for testers’ individual SNPs.
  • I took another stab at estimating dates to common ancestors based on the way that FTDNA has the SNPs and Private Variants for the five Butler/Whitson BigY testers. These results were very similar to what I came up with in a previous Blog.

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