How do you explain this unusual Y-DNA result

+6 votes
My uncles Y-67 test results matched mine and my sons 65/67. The only mismatches occurred on DYS455 and DYS531.  My sons an myself have zeros in those two locations while my uncle had an 8 at DYS455 and an 11 at DYS531.  We matched exactly on the other 12 deletions and everyone of the other locations tested.

How is this possible.  My uncle is my father's youngest brother. He is the sole surviving son of my grandfather's family.  I received my Y-DNA from my father with 14 deletions which I passed on to my sons. Since my grandfather passed on this trait to my father (the oldest boy), how do you explain how my uncle who had the same father could receive an 8 at DYS455 and and 11 at DYS531? There was a 20 year age difference between my dad and my uncle.  Once DNA is lost it cannot be transmitted to the next generation.

I am looking for a good explanation of how this could occur.
in WikiTree Help by Ran Prouse G2G6 (7.3k points)

It seems like I hear about something happening, once in a while, that goes beyond the undoubtedly-simplified explanation that they feed to us lay people. Not that we should believe that the experts who develop these things really know EXACTLY what's going on anyway - it's still a pretty new field.

All I can think - considering that you say there are a number of men with these deletions outside you immediate family - is that you guys have something in the mix that trips up the physical mechanism that the testing companies use to measure those locations, but that your uncle has lost whatever it is that trips it up.

We take for granted that these tests flawlessly measure what's actually there, but no physical process is perfect. I imagine that the measurement of a microscopic - and incredibly complex - molecule is perfect place for having the process run into unusual case where it fails.

But that's all speculation on my part, of course, but think about how crazy it is that they can do this at all, and how relatively cheaply they make a great many of these measurements!
Hi Rand,

You and I have communicated about your project. If I'm reading correctly your Uncle is the only surviving male of your father's line tested. If this is the case then it is possible the deletions happened with your DNA and it could be your father did not pass on those deletions to you, but you now have them and so do your sons.

Sherrie Mitchell-17863

1 Answer

+5 votes
I'm not sure how you're using the term "deletions" here. You mean repeats? Zero repeats sounds like a lab error.
by Living Buckner G2G6 Mach 5 (57.0k points)
NO lab error!  Our results are very unique. Nineteen deletions through the Y-111 test. Eight in Y-37, Six more through Y-67 and the final 5 in the Y-111. Take a look at the Multiple Deletion Project at FTDNA.  This marker has the potential to identify my family line and make connections where brick walls have stalled progress.
STR deletions are actually pretty common. I think what you mean is a null, when the primer can't find a particular set of STRs. There are several reasons that can happen, and sometimes it can be simple SNP rather than all the STRs getting wiped out. I think it's pretty rare that whole STR regions actually get deleted. Sometimes they change the reporting on nulls, and that might be what happened here. The ISOGG wiki notes ( that FTDNA changed labs and the primer on DYS439 changed, so that a lot of former nulls are now being reported as 12 repeats. That could be what happened here, that the primer changed, or they used different labs.

A deletion here and there may be pretty common, but multiple deletions of a whole section is not. 

I have results of 14 individuals who have multiple deletions in the same locations!  The lab used was FTDNA. The resulting multiple deletions have been helpful markers to identify a common ancestor or a connection to families with different surnames. We are having success in identifying NPEs because of the uniqueness of our results.

I understand the reluctance to accept these results as accurate. Fathers and sons have take the Y-DNA test at different times with identical results.

I believe the results deserve to be taken seriously, without suspicion, maybes and could be if.....

Multiple Deletions are very rare, but they are real! It is time for serious consideration be given to the benefits of these results.

The locations between 6,868,881 and  8,851,357, in build 37, returned zero results. 

If you have multiple whole sections missing, it's probably not multiple deletions but rather one really big event. I'd probably get the SNPs done. STR amplification relies on a lot of assumptions about how the genome is laid out, so it doesn't deal with weird situations very well. It's a cheap but coarse tool.

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