These numbers seem high to me. This is not a strictly comparable breakdown, but I downloaded Ancestry Finder matches from 23andMe for a child and two parents. The child had 224 segments with names attached, 65 of which were not found in either parent. By segment size: > 7 cM: 2/73 3% 6-7 cM: 9/39 23% 5-6 cM 54/112 48% I don't personally have a father/mother/child trio at FTDNA, and I don't want to go through Chromosome Browser to get all the segment sizes. But at the match level, the worst case I have seen was 17/70 matches found in the child but not in either parent. I don't know how tedious this would be for you, but what if you limited segments to those with 700+ SNPs (the threshold at 23andMe). Also, I noted in another message in this thread that I saw a case where the parent clearly had a large identical segment match at GEDmatch, which somehow failed to meet FTDNA's (unknown) criteria for reporting a match. Ann Turner On Mon, Jan 9, 2012 at 12:28 AM, Tim Janzen <[email protected]> wrote: > Dear All, > I decided to download the latest Family Finder data for my wife's > parents, my wife, my parents, and me yesterday. I then analyzed the data > so > see how many people appear in the FF match lists for my wife and me who > don't appear in the FF match lists our parents. I then used that data to > create my own statistics regarding the percentage of matches at various > segment lengths in cMs to see how my data compares to the statistics that > John Walden generated. > Here are my results: > cMs %IBD %IBS > >11 100 (52/52) 0 > 10-11 80 (12/15) 20 > 9-10 93 (25/27) 7 > 8-9 81 (34/42) 19 > 7-8 46 (11/24) 54 > 6-7 67 (4/6) 33 > 5-6 40 (6/15) 60 > 4-5 20 (10/51) 80 > 3.5-4 17 (11/66) 83 > > Below are John Walden's results from his analysis that I posted in > another message several days ago: > cM %IBD %IBS > 10 99 1 > 9 80 20 > 8 50 50 > 7 30 70 > 6 20 80 > 5 5 95 > > My results would suggest that a higher percentage of matches under 9 cMs in > length are IBD than John's analysis would suggest. In any case, it would > appear that a significant percentage of matches in the 6-9 cM range are > IBS. > If any of the rest of you have two parent/one child trio data in Family > Finder it would be interesting to see if your results are similar to mine. > > Sincerely, > Tim Janzen > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Jim Bartlett > Sent: Friday, January 06, 2012 8:19 PM > To: [email protected]; [email protected] > Subject: Re: [AUTOSOMAL-DNA] SUBJECT: How do you work a 5 way FF match with > few clues ? > > Sam > > What is the "big issue" about unphased data? As always, my reference is to > genealogy. > > I can see where it would help, some, to know if a match was on my Dad or > Mom's side, but SURNAMES and geography can help there, too. And even if I > knew which parent my match was on, I still wouldn't know which grandparent. > > Jim > > > > ______________________________ > For answers to Frequently Asked Questions about mailing lists, please see: > http://dgmweb.net/MailingListFAQs.html > > > ------------------------------- > To unsubscribe from the list, please send an email to > [email protected] with the word 'unsubscribe' without > the quotes in the subject and the body of the message >

Dear Ann and others, I decided to download the Ancestry Finder matches from 23andMe for my parents, my wife's parents, my wife, and me. I then sorted the data to remove the anonymous matches. I then compared my wife's and my matches to our parents' matches to see if any of my wife's or my matches in Ancestry Finder were not found in the Ancestry Finder matches for our parents. Below is an analysis of the results: cMs %IBD %IBS >10 100 (51/51) 0 9-10 87 (14/16) 13 8-9 91 (31/34) 9 7-8 79 (33/42) 21 6-7 67 (65/97) 33 5-6 43 (80/185) 57 This information complements the FTDNA Family Finder data I recently posted at http://archiver.rootsweb.ancestry.com/th/read/AUTOSOMAL-DNA/2012-01/13260977 07 and your data below. Overall the results are similar between both analyses except that I got a significantly higher percentage of matching segments that are IBD between 7 and 8 cMs with 23andMe data than I got with Family Finder data. Collectively, your data and my data suggest that John Walden's projections for the percentage of matching segments that are IBD between 5 and 9 cMs are significantly on the low side. It would appear that almost all matches over 11 cMs in length are IBD. It seems prudent to look for genealogical connections for all matches between 5 and 8 cMs, but we shouldn't be surprised if we can't find a genealogical connection due to the fact that either the connection is too far back in time or because the match was IBS in the first place. If other people have two parent/one child trio data at 23andMe or Family Finder it would be interesting to see their analyses as well. Sincerely, Tim Janzen -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Ann Turner Sent: Monday, January 09, 2012 8:47 AM To: [email protected] Subject: Re: [AUTOSOMAL-DNA] SUBJECT: How do you work a 5 way FF match with few clues ? These numbers seem high to me. This is not a strictly comparable breakdown, but I downloaded Ancestry Finder matches from 23andMe for a child and two parents. The child had 224 segments with names attached, 65 of which were not found in either parent. By segment size: > 7 cM: 2/73 3% 6-7 cM: 9/39 23% 5-6 cM 54/112 48% Ann Turner