Archiver > GENEALOGY-DNA > 2010-03 > 1268944909

From: "Sandy Paterson" <>
Subject: Re: [DNA] Expected NPE's Over 800-1000 Years
Date: Thu, 18 Mar 2010 20:41:49 -0000
References: <> <><013c01cac6d7$ee343e70$5e82af48@Ken1>
In-Reply-To: <013c01cac6d7$ee343e70$5e82af48@Ken1>

Of course you're right, Ken, but to be fair, the example given clarifies this.

But this isn't where it ends. In land-owning families, there will have been instances where a family daughtered out. I can't see a good Scotsman (for example) simply handing over the family estates to oblivion. So one of his daughters retains the surname and the husband changes his surname accordingly. That's not an NPE. So the 49% falls even further.

To me, this makes a mockery of the belief that family A or clan B are, or should be a particular haplogroup or have a particular DNA signature.


-----Original Message-----
From: [mailto:] On Behalf Of Ken Nordtvedt
Sent: 18 March 2010 20:17
Subject: Re: [DNA] Expected NPE's Over 800-1000 Years

You mean (1-p) raised to the nth power? Some may read your "(1-p)n" as n
times (1-p)

----- Original Message -----
From: "Nancy Kiser" <>

> Hi, Lindsey,
> The probability that a living male will carry the Y-signature of his
> surname’s progenitor from n generations ago is (1-p)n, where p is the
> fractional probability of a non-paternal event at each generation. So
> first you have to decide what rate of NPEs per generation you think is
> reasonable and then you have to decide how many years constitute a
> generation. I have read where some experts think 2% to 3% per generation
> is a reasonable estimate of NPEs and many experts use 25 to 30 years to
> calculate a generation.
> Nancy Kiser

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