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Archiver > GENEALOGY-DNA > 2014-08 > 1409124325


From: "Tim Janzen" <>
Subject: Re: [DNA] AncestryDNA
Date: Wed, 27 Aug 2014 00:25:25 -0700
References: <00c701cfc189$4f625b40$ee2711c0$@oneotaslopes.org>
In-Reply-To: <00c701cfc189$4f625b40$ee2711c0$@oneotaslopes.org>


Dear Eric,
Below is the information that Kenny Freestone of Ancestry.com included in his presentation at the NGS convention in May per Angie Bush:

Parent/child (parent, child – immediate family member)
Immediate Family (immediate family to close family)
Close Family (close family to 1st cousin)
Second cousin (1st to 2nd): 200,000,000 base pairs
Third cousin (3rd to 4th): 150,000,000 base pairs
Fourth cousin (4th to 6th): 100,000,000 base pairs
Distant cousin (5th to 8th)(moderate confidence): 30,000,000
Distant cousin (5th to 8th)(low confidence): 20,000,000
Distant cousin (5th to 8th)(very low confidence): 5-10,000,000

The switch from 5 million base pairs as the criteria for a match to 5 cMs occurred approximately in January.

I agree with Shannon Christmas that we should strongly encourage our matches at Ancestry.com to transfer their raw data files over to GEDmatch. I do this for every match that I correspond with at Ancestry.com. I estimate that about 5% of Ancestry.com customers have already done that. Hopefully this percentage will increase over time. I do the best that I can with the pedigree charts at Ancestry.com, but I find that the lack of matching segment data for all my family's matches at Ancestry.com significantly undermines the usefulness of all of the AncestryDNA test since I can't put any of my matches at Ancestry.com into triangulated groups.
Sincerely,
Tim Janzen

-----Original Message-----
From: [mailto:] On Behalf Of Eric S Johnson via
Sent: Tuesday, August 26, 2014 4:56 PM
To:
Subject: [DNA] AncestryDNA

I just noticed the results of Dad’s AncestryDNA atDNA test are in. As was noted a couple days ago, they’re divided into categories—mine are:


Do we know what the precise criteria are which Ancestry uses to make these divisions (number of shared HIRs above some threshold; total shared DNA; size of longest shared HIR; …)? (I gather AncestryDNA measures shared HIRs in mbp instead of cM, but that’s all I’ve been able to find out online.)


Can anyone share their recommendations for how deep it’s worth digging into this pile of matches? (Off the bat, I sent a message to everyone in the top two groups, and all five of the matches with “hints.”) And, is how high a match is in this list the only criterion to use when making this decision/cut? (I can see “last logged in,” whether there are any hints, and whether they have a tree (and how sizeable it is)—do these (statistically speaking) get reflected in how likely someone is to be a “useful” “DNA relative”?)


Best,

Eric



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