From roots-in@roots-l.rootsweb.com Wed Sep 6 10:19:47 2006 Received: from mail.rootsweb.com (mail.rootsweb.com [192.168.65.34]) by admin.rootsweb.com (8.12.8/8.12.8) with ESMTP id k86GJljb000599; Wed, 6 Sep 2006 10:19:47 -0600 Received: from roots-l.rootsweb.com (roots-l.rootsweb.com [66.43.16.22]) by mail.rootsweb.com (8.13.4/8.13.4) with ESMTP id k86GJXBX001364 for ; Wed, 6 Sep 2006 10:19:33 -0600 Received: from roots-l.rootsweb.com (roots-l [127.0.0.1]) by roots-l.rootsweb.com (8.12.10/8.12.10) with ESMTP id k86DcaFI007715 for ; Wed, 6 Sep 2006 09:38:36 -0400 Received: (from roots-in@localhost) by roots-l.rootsweb.com (8.12.10/8.12.8/Submit) id k86DcasG007714 for roots-approved@rootsweb.com; Wed, 6 Sep 2006 09:38:36 -0400 Received: from lists5.rootsweb.com (lists5.rootsweb.com [66.43.27.41]) by roots-l.rootsweb.com (8.12.10/8.12.10) with SMTP id k86BWIFI007307 for ; Wed, 6 Sep 2006 07:32:18 -0400 Received: (from slist@localhost) by lists5.rootsweb.com (8.12.8/8.12.8) id k86ECw4o023416 for roots-in@roots-l.rootsweb.com; Wed, 6 Sep 2006 08:12:58 -0600 X-Envelope-From: astronautix@gmail.com Wed Sep 6 08:12:58 2006 Received: from mail.rootsweb.com (mail.rootsweb.com [192.168.65.34]) by admin.rootsweb.com (8.12.8/8.12.8) with ESMTP id k86ECwjb023407 for ; Wed, 6 Sep 2006 08:12:58 -0600 Received: from nf-out-0910.google.com (nf-out-0910.google.com [64.233.182.185]) by mail.rootsweb.com (8.13.4/8.13.4) with ESMTP id k86ECsss021612 for ; Wed, 6 Sep 2006 08:12:54 -0600 Received: by nf-out-0910.google.com with SMTP id n15so237065nfc for ; Wed, 06 Sep 2006 07:12:54 -0700 (PDT) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:mime-version:content-type:content-transfer-encoding:content-disposition; b=IVZRFPutX7PmbTqdva2lKEHz8wAo6n5atNebtTogztUuJwEtnrEn6z5OI3jRxBEBh903BTOWd3ZbGx7TS2/1aciko4JvLezGUtSQa211VAAkLvEFM1tDvb4TJpnHOb4h8cLaoxUgYmkBtlr61Aj+ybT4CHlBRvD74OTu/HSNWFA= Received: by 10.49.8.4 with SMTP id l4mr941718nfi; Wed, 06 Sep 2006 07:12:54 -0700 (PDT) Received: by 10.49.63.3 with HTTP; Wed, 6 Sep 2006 07:12:54 -0700 (PDT) Message-ID: <7a4e8f310609060712n1653ce12k149651093fef26ef@mail.gmail.com> Date: Wed, 6 Sep 2006 16:12:54 +0200 From: "Mark Wade" To: ROOTS-L@rootsweb.com MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline X-Scanned-By: MIMEDefang 2.52 on 192.168.65.34 X-Scanned-By: MIMEDefang 2.52 on 192.168.65.34 Sender: roots-in@roots-l.rootsweb.com Subject: [ROOTS-L] False Paternity and Y-DNA matches Undoubtedly this has been covered already, but: I had gotten successive 12, 25, and 37 marker tests. None of the surnames matched. FTDNA gives a kind of breezy explanation for this, but then I remembered a news article some time ago that mentioned the surprisingly high false paternity recorded when 100% DNA testing was done (e.g. the father reported on the birth certificate was not the father according to DNA test - good summary of the issue at this link): http://www.canadiancrc.com/articles...ret_14DEC02.htm Anyway, I decided to do a little math. The percent likelihood of a common genetic father by number of generations (per FTDNA's FTIP) versus the likelihood that the person in the same generation would have a different surname (e.g. not be in the geneaologically-documented line). The results for a 15% false paternity rate were (Gen = Generation number; FalseDad% = likelihood that the geneaologically-documented ancestor is not, in fact, your biological ancestor; FTIP = likelihood that two persons with the identical 25 markers have the same biological ancestor): Gen FalseDad FTIP 4 48% 61% 8 73% 85% 12 86% 94% 16 93% 98% 20 96% 99% 24 98% 100% As you can see, it is extremely likely that you will have a high probability FTIP match with someone, and they would have a different surname (due to false paternity records). In my case, I had a 25-marker match with four other men, all of whom have different surnames. Of course in the case you can compare geneaologies, you can rule out a connection if the ancestors were living in different states or countries... but if you've got an intersection of geographical location but different surnames, it might mean a dark and ancient wife's secret has been uncovered... Maybe this has all been discussed here before... for those of you who think 15% is too high (some studies show the rate to be as high as 30%!) the corresponding figures for 5% and 10% rates of false paternity are: 4 19% 34% 8 34% 57% 12 46% 72% 16 56% 81% 20 64% 88% 24 71% 92%