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Old 18th February 2017, 11:06 AM
NCroots NCroots is online now
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Join Date: Feb 2015
Location: North Carolina
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Originally Posted by benowicz View Post
Using the 30 year generation convention, they're probably all around 6 gen. out from the common ancestor. So roughly 16% percent chance. Not encouraging, but not out of the question.

I have a match at 37-markers with a distance of 3 (34/37). Using the TiP calculator, this gentleman & I are predicted to share a MRCA within 12 generations with a probability of 90.31% (within 24 generations at 99.82%).

Using the MRCA Calculator from the Clan Donald USA site, set for 37-markers distance of 3, I get an estimate of 9 generations at .072. That's without Cumulative Probability because I didn't know what that meant.

We suspect a NPE in our paternal lineage and nailing down the exact date of our MRCA would help in proving or disproving our theory. Which is more reliable, the TiP Calculator or the MRCA Calculator?
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Old 18th February 2017, 04:27 PM
benowicz benowicz is offline
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Actually, that chart I copied and pasted fits the fact situation you present of 2 donors with GD of 3 at 37.

The Macdonald calculator uses very slightly slower mutation rates than the TIP calculator. I think the TIP calculator may be using more up-to-date information, but the differences aren't normally enough to get me bothered for such a rough estimate.

The percentages posted in my chart are cumulative. 36.9% at 9 generations. The 0.072 % figure that you quote seems as if it is the non-cumulative figure. Apples and oranges.

I only ever pay attention to the cumulative figure. You can look up and compare the difference between the technical definitions of cumulative and non-cumulative risk if you want, but a good, safe approach is to go with the cumulative percentage. I think most people only pay attention to the cumulative.

Either TIP or Macdonald are good choices. TIP's mutation rates may be more up-to-date, but Macdonald's are close enough, and probably considered more conservative. Which I guess is good.
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