Hi Roy, all,
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It's been on my list of things to do to revise the ages for R-A6535 and the broader R-Y17443, given the addition of some more testers. For now, the dates I previously computed are probably still more accurate than those on Discover.
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The Discover ages don't have the constraints from genealogy added, which makes a big difference in R-Y17443. Single genealogies push back the TMRCA, since they dictate that common ancestors must be before a certain point. Triangulated pairs of genealogies that dictate who the MRCA was actually bring the TMRCA for surrounding haplogroups forward in time.
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This latter reason is a little harder to understand, but better considered by example: if you have a TMRCA that is 300 +/- 100 years, then all is fine but if you increase the uncertainty to 300 +/- 400 years, then you have a problem: the TMRCA can't be less than zero. The errors become asymmetric and, rather than a TMRCA of 300 +/- 400 years, you end ?up with something more like a TMRCA of 500 +/- 400 years. Consequently, providing more data on young haplogroups (either through more tests or using genealogy) then it tends to bring the TMRCAs closer to the present.
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I still expect the R-FT114487 TMRCA to be roughly co-incident with the Norman Conquest - perhaps slightly before or after.
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Cheers,
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Iain.
