Archiver > GENEALOGY-DNA > 2010-02 > 1266267159

From: (John Chandler)
Subject: Re: [DNA] FTDNA v. ISOGG R1b haplotree comparison updated
Date: Mon, 15 Feb 2010 15:52:39 -0500
References: <F815B276748D4912B0D9AE7A22D78E31@PC><A1B31D06576844FCB561CAB2CBD40F7E@elizabethod>
In-Reply-To: <A1B31D06576844FCB561CAB2CBD40F7E@elizabethod>

> 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

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