More On My Butler Brother-In-Law’s BigY 700 17 Private Mutations

My brother-in-law’s BigY 700 test results came in on February 14th this year. One thing that seems strange to me is that he has 17 private variants. This leads me to believe that FTDNA has not yet finished it’s manual review. In my previous Blog, I didn’t have access to my brother-in-law’s results. Now I do.

Private Variants

Normally there should not be any private variants or perhaps one at the most between a father and son. So where did these come from? My guess is that they could be from earlier YDNA branching. Private variants show as position numbers on the Y Chromosome. Here are the first 10 belonging to my brother-in-law:

I’ll check the first position at YBrowse, to see if there is any more information there:

This is interesting, because this appears to be a new, unnamed SNP. Here are my brother-in-law’s test results:

They look like good results. I’m starting to guess now, but perhaps my brother-in-law picked up a new SNP that no one has ever tested for before.

Let’s try the next position:

This looks new also.


This position at least gave me a SNP number:

Here are some more details:

This tells me that this is a named SNP, but it is a new one as of 2020. This SNP was probably named as a result of my brother-in-law’s BigY test.

I’m beginning to see a trend here. Here is Richard’s csv file for that position:

Richard’s test didn’t cover as many YDNA locations as it was an older test. So the position that his son tested for is new.

Here is a spreadsheet for looking at my brother-in-law’s new private variants:

I’m going down the list. The private SNP at 26M was discovered earlier by a different company:

Summary of My Brother-In-Law’s New 17 Private Variants

Notice the last column. That is the one that says that Richard’s test never covered the position or new SNP that his son has. That explains the 17 new private variants.

Spreading the Net Wider to England

The next logical step is to check my brother-in-law’s private variants against the other BigY Butler tester in England.

Now I’m getting somewhere. The question mark means that EB was tested for the position number but that the results were inconclusive. EB was not tested for the first two position numbers, so they remain without a SNP name. I assume this is where my brother-in-law could match his father or theoretically have a new private variant. That means that my brother-in-law could end up with two private variants down from 17.

In a previous Blog, I had predicted that these new SNPs may go in the Block above Batt under I-Y128591 or even above that. This is still a good place for these 15 SNPs.

Going Up a Level To Batt

I can go one level further. This sheds some further light:

The question marks mean that there was not enough information to say that the tester was positive or negative for a mutation at the location. However, the fact that Batt had a possible mutation at every position of my brother-in-law’s private variants suggests that my brother-in-law will end up with zero private mutations. Mystery solved.

Summary and Conclusions

  • A comparison between my brother-in-law and his father showed that my brother-in-law had 17 private variants. However, that was because those 17 locations were not covered in my father-in-law Richard’s BigY test.
  • A comparison between my brother-in-law and his next closest Butler match showed that match had been tested at 15 of those locations, but the results were inconclusive.
  • I then went out another level and found that Batt had been tested at every location of my brother-in-law’s private variants, but the results were inconclusive at all of those locations.
  • It is likely that my brother-in-law’s test results will confirm each questionable test and that he will end up with no private variants.
  • I guessed where the extra 17 SNPs will end up, but I don’t have enough information to be sure that they will be in the I-Y128591 Block or above that.


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