GENEALOGY-DNA-L Archives

Archiver > GENEALOGY-DNA > 2010-11 > 1289254671


From: Jim Bartlett <>
Subject: Re: [DNA] "Relationship Range" Confidence Level
Date: Mon, 08 Nov 2010 17:17:51 -0500
References: <201011080050.oA80obfJ030681@mail.rootsweb.com><4CD81B95.5060600@ehv.com><DE8C3B93-759A-4E7A-90C6-4E5E3A1CF8B8@verizon.net><4CD868F5.3080904@ehv.com>
In-Reply-To: <4CD868F5.3080904@ehv.com>


Harold,

I showed the predictions and the actual for all 11 below. When I said "FTDNA said 2C", that means FTDNA's prediction was 2nd cousin.

Double cousins, or multiple common ancestors, gives more matching DNA and tends to skew the prediction earlier. They predicted 2C, which is probably the same as two 3C. So for Colonial Virginia, where one might have several common ancestors (including some who are not know about), each of them may contribute some DNA blocks that would increase the total cM. However, having said that I will also point out that 9/11 of my matches only shared one DNA block over 7.7cM with me. So that single large block probably came from one ancestral couple or the other - not both. And since all of those large blocks, so far, are different, I can't tell which ancestor it might be.

Hope this helps,

Jim - Sent from my iPhone - FaceTime!

On Nov 8, 2010, at 4:17 PM, "E. Harold Vannoy" <> wrote:

> Thanks for the reply Jim. For the 11 new cousins that you mention, would
> it be possible to also get the "Relationship Range" that FTDNA
> predicted? This would tell me how well their "Relationship Range"
> estimation worked out.
>
> I don't recall seeing anything written on the effect of "double cousins"
> on the amount of DNA that is inherited. Has anyone seen any information
> on this subject?
>
> Thanks again,
>
> Harold
>
>
> On 11/8/2010 12:57 PM, Jim Bartlett wrote:
>> Harold,
>>
>> So far I've confirmed 11 new cousins back to common ancestors, and am working on the 12th; all with Family Finder. The ancestral paths go through 34 different surnames.
>>
>> Predicted vs actual:
>>
>> FTDNA said 2C - turned out: double 3C (2 brothers m 2 sisters)
>>
>> FTDNA said 4C - turned out: 10C-1
>>
>> FTDNA predicted the other 9 as 5th or more - turned out: 6C-1, 6C-1/7C-1 (double cousin); 7C; 8C-1; 8C; two 9C; two 10C.
>>
>> All but one of these is from Colonial Virginia. None of these has any block over 7.7cM in common with or overlapping any others - all large blocks are on separate chromosomes and/or at separate places. Many of the smaller blocks are shared by several matches.
>>
>> Like you, I'm interested in what others are finding.
>>
>> Jim - Sent from my iPhone - FaceTime!
>>
>>
>
>
> -


This thread: