Archiver > GENEALOGY-DNA > 2010-02 > 1266445858

From: Wayne Kauffman <>
Subject: Re: [DNA] FTDNA will introduce Family Finder
Date: Wed, 17 Feb 2010 14:30:58 -0800 (PST)
References: <><FF63B9BB41BE44BC999F83D59177C32B@TERRYSHUTTLE>
In-Reply-To: <FF63B9BB41BE44BC999F83D59177C32B@TERRYSHUTTLE>

Reality check.

There are a couple of items that individuals need to factor into a decision to utilize RF or FF for ancestral and especially for surname based research efforts. The primary point is that neither product will be able to consistently answer genealogical questions 4+ generations into the past on the basis of test results from 2 distantly related individuals. In order to positively identify a relationship one will need to test multiple descendants from several lines to establish older genealogical relationships.

The presence of more than one common shared ancestor between the tested participants will complicate the analysis process and may require additional participants to clarify the origin of common IBD segments. For the tested individuals the analyst will need to factor in the effects of pedigree collapse on the presence, or lack thereof, of IBD segments. Within the Amish/Mennonite project at 23andMe we are slowly gaining a practical understanding of how pedigree collapse alters what we would be expected to be seen.

While FF has the advantage of working off of the existing FTDNA project framework it will be sometime before the size and diversity of the FF database equals that which is present within 23andMe's structure. RF's diversity is a big positive asset for delivering a relevant distant match to a submitted sample. When one is looking for the surname of a female ancestor having a diverse dataset increases the odds for a match.

Finally the differences in the technology base for comparing IBD segments between RF and FF will take some time to sort out. Cross chip comparison of results will need to account for the inherent bias present in the particular chip. An analysis of this type of bias can be found in this paper - To the geneticist the FF raw data may the window into evaluating copy number variants but I am not sure on this topic.

- Wayne kauffman

From: Terry Barton <>
Sent: Wed, February 17, 2010 3:19:51 PM
Subject: [DNA] FTDNA will introduce Family Finder

I have gotten a flurry of questions about this test, so I have posted my
understanding on my blog. (based on 4 "Complete Edition" tests at 23andMe,
FTDNA's info releases, a couple of conversations with FTDNA, two Beta tests
on order and a little supposition)

If you find my posting useful, feel free to share it with those asking you
questions. If you have supplemental info, feel free to post it as a reply -
or to let me know offline and I'll update my posting. And - if you spot an
error, I really want to fix that!

Terry Barton

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