Archiver > GENEALOGY-DNA > 2010-03 > 1268943594

From: Nancy Kiser <>
Subject: Re: [DNA] Expected NPE's Over 800-1000 Years
Date: Thu, 18 Mar 2010 13:19:54 -0700 (PDT)

Yes thanks Ken

Sent from my iPhone

On Mar 18, 2010, at 2:16 PM, "Ken Nordtvedt" <> wrote:

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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