Monday, April 17, 2017

And AncestryDNA's estimated Amount of Shared DNA is.....

In last Wednesday's blog post I asked if anyone wanted to take a guess at how many shared cMs a cousin match at AncestryDNA was estimated by Ancestry to have.  The match is kin to me 5 different ways. On reevaluating I found yet another shared Double line.  The only person who posted a guess via the comments was Randy Seaver,  so regardless,  he is the closest.  :-)  Perhaps the question was intimidating--DNA research can be like that sometimes.  Randomness.  It doesn't always follow logic or mathematical principles inheritance-wise.

The match shared the following connections with me

5C1R(2x)------Nathan Frizzell & Margaret Deason(my 4Gr his 5Gr) (*)
4C---------------James Morrow & Margaret Sutton(both 3rd Grs)
4C---------------James Jakes & Nancy Harger(both 3rd Grs)
4C1R-----------James Jakes & Nancy Harger(my 3rd Gr= his 4th Gr)

Additional discoveries of
6C---------------James Knox & Elizabeth Craig(Eoff line goes back to them)
6C1R-----------James Knox & Elizabeth Craig(see above)

I used the BLUE for the relationships that were thru my PGM's Dad and the PINK
for the ones that were thru my PGM's Mom.

Typically half of your 4th cousins won't even share DNA with you.
If I had guessed I would have taken the average for all the relationship amounts

4C=13.28  (times 2)
5C1R=1.66 (times 2)
6C= .83
6C1R= .42
Estimated Total that way would have been 37.77 cMs
Which would put me in really close to Randy's guess.  In reality I share 114 cMs across 9 segments as shown below.  That is a typical amount for 2nd Cousins once removed.

I should also note that the 114 cMs made it thru the Ancestry "cut" so it doesn't include anything that is in what they consider to be a "pile-up" region.  Ancestry matches will not include X Segments so there may still be more in common along the X where it is in the x inheritance path.  In typically fashion my sister has done it again and matched them more. The match shares 132 cMs with her across 7 segments.

I really need to see this match at GEDmatch. I think this is a great exercise in how large segments are passed.  In my daughter's matches there are many of the Wildes/Wilkinson descendants who share a large segment of 50 cMs on one chromosome.  Randomness for sure!

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