Genelach Dáil Cuinn Project™ Forum

Shane,

Firstly, welcome! I'm glad you made it over to this forum.

Secondly, please look at your portion of the DCG Cladogram. Apparently you had 2 new mutations that your father does not. We still don't know what the mechanisms are that cause Y-DNA mutations, so you can tease your father however you want about what he was doing in the time frame leading up to your conception.

BTW, are your father's BigY 700 results uploaded to the Y-DNA Data Warehouse yet?

Shane,

No worries. Both of your unique mutations are SNPs, not STRs, INDELs, or SUBs.

Re the frequency of mutation, that one source is WAY out of date. The current SNP (and only SNPs) mutation rate is about one new one every 90 years for the coverage regions of the BigY 700 test, and about 125 years for the smaller coverage regions of the BigY 500 test. Keep in mind those are only a median time and can vary significantly. So you having 2 unique SNPs different than your father is not out of line at all. Remember, Keith Johnson saw something similar between himself and his son and THAT son's son.

I did some looking at Shane's father's results and his father appears to share those but they don't seem to show up on FTDNA's tree (at least I couldn't find them). This what I posted on the AF earlier...
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Shane, I looked at your results on the Big Tree) it shows both of these (https://www.ytree.net/SNPinfoForPerson. ... sonID=7755), this is likely where David pulled them from but your father doesn't seem to be on the Big Tree or submitted to the Y-DNA Warehouse, and the Big Tree often goes deeper. I also looked at your father. I also looked at your fathers results on FTDNA, and he is positive for these at FTDNA as well, but FTDNA doesn't appear to have moved you down. It says that both are on the Y-Tree, but I couldn't find either of them on FTDNA's trees when I looked (not sure why they don't). However, your father does share them but apparently FTDNA isn't reflecting that at least as far as the data David can access.

Your father's results
SNP Name Derived? On Y-Tree? Reference Genotype
BY117344 Yes (+) Yes G A
YP5645 Yes (+) Yes C G

If you add your father's results to the Big Tree when David updates the cladogram it likely would reflect it, but right now it doesn't appear those are in the FTDNA Y-Tree despite saying they are. I haven't run this by David, but have looked at your results on the Big Tree and your father's here on FTDNA.

Gráinne,

Thanks for checking into that! You are completely correct. I don't see them anywhere on FTDNA. It is stuff like this that does NOT give me the warm and fuzzies about FTDNA results OR their Haplotree.

Hopefully Shane's father will show up on The Big Tree soon and we can clear this up.

I haven't yet run across 2 SNPs from father to son. I did happen to form 1 SNP from my father to me (tested him and my brother for it and both are negative). My father wasn't particularly old when having me - 31 years of age...and 26 when having my brother.

Sometimes the chances of these mutations, both Y-STR and Y-SNP can increase in older fathers. These largely arise from copy mutations of the Y chromosome in the male gametes used to conceive. There are papers showing that the mutation rates increase with age of a father...however, it wouldn't have been expected from mine going from only 26 to 31. Now if he was 70-80+ when having me it would somewhat indicate a higher chance of happening. Interestingly my 4th great grandfather had a daughter at age 77, very well documented in birth/death certificates, probates, etc. I often wonder if it was a son what, if any mutations would have arose from such a late conceived son.

As it stands now my 4th great grandfather has my 3rd at age 23; and his last son that has living lines to test today at age 36. So probably wouldn't see much there.

Then again more generations of between testers can also increase opportunities for mutations more more strongly than simply older father's conceiving - at least in my experience of testing my extended family exhaustively.

Zack,

According to Dr. Iain McDonald, SNP formation moves at a fixed median rate of one new SNP every 82 years for BigY 700 tests. Of course, that is a median rate with a very wide variance. IDK about how the age of the father affects the formation, but Iain says that geography plays no role in the formation of SNPs at all. We still have a lot to learn in the area of SNP formations.

Admin wrote: Tue, 2020-May-26 7:40 pm Zack,

According to Dr. Iain McDonald, SNP formation moves at a fixed median rate of one new SNP every 82 years for BigY 700 tests. Of course, that is a median rate with a very wide variance. IDK about how the age of the father affects the formation, but Iain says that geography plays no role in the formation of SNPs at all. We still have a lot to learns in the area of SNP formations.

David,

I'm going on some studies of father-son pairs factoring in age of fathers. For example, this 2018 study showed a strong correlation with age of father conceiving a male child with an increasing rate of Y-STR mutation. It was an STR study but like all copy errors at conception it stands to reason that Y-SNP copy errors will be made as well. There are a large number of publications showing this with regards to autosome copy errors (mostly disease based studies).