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Archiver > GENEALOGY-DNA > 2010-02 > 1266277745

From: "Elizabeth O'Donoghue" <>
Subject: Re: [DNA] FTDNA v. ISOGG R1b haplotree comparison updated
Date: Mon, 15 Feb 2010 23:49:05 -0000
References: <F815B276748D4912B0D9AE7A22D78E31@PC><A1B31D06576844FCB561CAB2CBD40F7E@elizabethod><REME20100215155018@alum.mit.edu>

John, thank you for this. If we consider modal comparisons, rather than the
two chiefs themselves, then we could consider the figures I mentioned to be
the only differences, and they are all only one step differences -
discounting CDY, which is 36/37 vs 37/38.

Having said that, you could consider the 67 markers with which to compare.
I would hope that the span would be less than between 34 and 154, which is
so great at to be relatively useless in coming to any relevant conclusions.
What percent probability would that be?

Elizabeth

-----Original Message-----
From:
[mailto:] On Behalf Of John Chandler
Sent: 15 February, 2010 8:53 PM
To:
Subject: Re: [DNA] FTDNA v. ISOGG R1b haplotree comparison updated

> for the two haplotypes to diverge at 8 distinct markers in the
> first 25 (DYS391, 385b, 459a/b, 447 and 464a/b/c) and 2 in the last 30
> (DYS557, 565), disregarding CDYa,b and nevermind the other odd markers
where
> they individually differ, what are the probabilities?
>
> I know some of the math experts probably could tell us quite quickly.

It gets awkward if you start arbitrarily disregarding certain markers.
Therefore, the only quick answer I can give you would be based on the
first 25 markers as a package. Assuming the eight discrepancies are
all of one step each, the 95% confidence interval for the separation
between the respective MRCA's of the two groups is from 34 to 154
generations before those MRCA's lived, whenever that was.

Note: it is **not** generations before **present**, but generations
before the respective founders. If they didn't live at the same
time as each other after all, then you can just split the difference
and call it 34 to 154 generations before their average time.

The limits would naturally be tighter if you would specify the number
of discrepancies for the whole 67-marker set (and whether any of the
differences are of more than one step).

John Chandler