GENEALOGY-DNA-L Archives

Archiver > GENEALOGY-DNA > 2006-08 > 1154611773


From: "Ken Nordtvedt" <>
Subject: Re: [DNA] research strategy for genealogists
Date: Thu, 3 Aug 2006 07:29:33 -0600
References: <00e001c6b6cc$c86e6720$6401a8c0@HP>


From: "Diana" <>

Let's look at a possible scenario, using the
> 13/15 match and some (yes) unrealistic counts to make the patterns easier
> to see
> in this email...
>
> Subject A: 5 5 5 5 5 5 5 5 5 5 5 5 5 11 15
>
> Subject B: 5 5 5 5 5 5 5 5 5 5 5 5 5 12 14
>
> The typical assumption would be that both individuals differ from a common
> ancestor who looks something like this:
>
> Common Ancestor: 5 5 5 5 5 5 5 5 5 5 5 5 5 11 14 [or 12 15 on last two
> markers - KN]
>
> Trouble is, it is just as likely that the ancestor of each looks like
> this:
>
> Ancestor of A: 5 5 3 5 5 2 6 5 4 5 5 5 5 11 15
>
> Ancestor of B: 4 5 5 5 6 5 5 4 5 5 5 5 5 12 14

[This latter possibility is not "as likely". Each mutation costs you a
factor of about "mG" with "m" being the marker's mutation rate and "G" being
number of generations back to the ancestor under consideration. For
genealogical time frame, "mG" is a very small number - KN]


This thread: