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Ancestry vs FTDNA -- Matches sharing over 100 cM

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  • Ancestry vs FTDNA -- Matches sharing over 100 cM

    I have over 60 pages - with 30 profiles per page -- of folks at FTDNA who share over 100 cM with me - even if I subtract the Kits I ordered for relatives, and the few others I immediately recognized as known relatives.

    At Ancestry, I have 6 matches with over 100 cM shared with me - plus one that rounds up to 100 cM shared (including two recognized known relatives).

    Moreover, a relative whom FTDNA shows as sharing 133 cM, Ancestry shows as sharing 71 cM
    (on GEDMatch, we are shown as sharing 101 cM for my Kit from FTDNA - both for the relative's Kit from FTDNA and for the relative's Kit from Ancestry)

    Is this typical?

  • #2
    (possibly should say - number on GEDMatch is from the 1-to-many Comparison)

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    • #3
      My largest match at FTDNA is 87 cM followed by 79, 65, 64 and 64. I have 1076 total matches.

      My largest match at Ancestry is 380 cM followed by 173, 151, 123, 117 and 92.

      It appears that all my 2nd cousin type relations tested at Ancestry and not one is on GEDmatch.


      100 cM is Second cousins once removed. You don't have 1800 Second cousins once removed.

      You have endogamy and/or pileups (IBP). Ancestry Timber filters out the pileup matches.

      Put the top 100 matches into the chromosome browser at GEDmatch and see how they match you.

      I bet you are looking at pileup city.

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      • #4
        100 cm is a 3rd cousin

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        • #5
          You have over 60 pages of matches at FTDNA who share over 100 cM with you??? Do you come from a highly endogymous population?

          My mother has none over 100 cM, outside of relatives I asked to test. There's one 98 cM (relationship unknown), but by the bottom of the first page the 30th match shares 61 cM, and the top 9 on the first page are relatives, the most distant being a 3rd cousin who shares 93 cM.

          My father's thirtieth match shares only 33 cM with him, the first 4 on the list being family members and number 5, sharing 153 cM with him turned out to be a 2nd cousin once removed. His 6th match shares 68 cM with him. My father is the son of Italian immigrants however.

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          • #6
            Originally posted by jimbirk View Post

            You have endogamy and/or pileups (IBP). Ancestry Timber filters out the pileup matches.

            Put the top 100 matches into the chromosome browser at GEDmatch and see how they match you.

            I bet you are looking at pileup city.

            Please provide info and/or link(s) to info on "pileup" - what that term means / what it is referring to, etc. Also to what "Ancestry Timber" is and what it is doing.

            As to putting matches in GEDmatch - nope, cannot do that - do not have access to most of the kits and definitely do not have the required permission to download their data from FTDNA (nor to upload it to GEDmatch).
            BUT - what is it you are suggesting I would see?
            Last edited by loobster; 10th December 2017, 08:20 PM.

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            • #7
              Originally posted by loobster View Post
              Please provide info and/or link(s) to info on "pileup" - what that term means / what it is referring to, etc. Also to what "Ancestry Timber" is and what it is doing.
              Not sure if I am allowed to post a link to Ancestry but simply search for "AncestryDNA Matching White Paper" on Google and you should find a pdf file explaining Ancestry's matching algorithm including information on Timber.

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              • #8
                Pile-ups are still DNA matches though, but Ancestry has decided on your behalf that you don't need to worry about any of them rather than let you analyse it yourself. Mind you, without a chromosome browser you can't sift through them anyway.

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                • #9
                  Originally posted by ltd-jean-pull View Post
                  Pile-ups are still DNA matches though, but Ancestry has decided on your behalf that you don't need to worry about any of them rather than let you analyse it yourself. Mind you, without a chromosome browser you can't sift through them anyway.
                  Thanks for saying that. I feel the same way.

                  Jack

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                  • #10
                    Originally posted by travers View Post
                    .. simply search for "AncestryDNA Matching White Paper" on Google and you should find a pdf file explaining Ancestry's matching algorithm including information on Timber.
                    Okay - so I found the White Paper - and it is 46 pages long, and seems to talk a lot about the Relationship Estimates and determing the correct Relationship Estimates -- but read thru 10 pages and skimmed more without seeing anything about determining the shared cM reported -- could someone help with a reference to what page or pages that is on?

                    Also, used search/find on it, and it did not find any reference to "pileup" in that White Paper - so could someone please explain that term as well, and how it connects.

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                    • #11
                      Originally posted by loobster View Post
                      Okay - so I found the White Paper - and it is 46 pages long, and seems to talk a lot about the Relationship Estimates and determing the correct Relationship Estimates -- but read thru 10 pages and skimmed more without seeing anything about determining the shared cM reported -- could someone help with a reference to what page or pages that is on?

                      Also, used search/find on it, and it did not find any reference to "pileup" in that White Paper - so could someone please explain that term as well, and how it connects.
                      "Pileup" is a colloquialism. The white paper refers to "excessive IBD" and "spikes" in section four (page 24+).

                      Comment


                      • #12
                        Matches conundum

                        I started out with FTDNA.Uploaed to Gene Cove,DNALand ,MyHeritage,Geni.Gedcom Genesis,Gene Plaza and Living DNA.
                        As a Jew,I have thousands of matches.I am amazed at how some people don’t get it.A few have responded looking for a common surname don’t upload or understand the next steps in this journey....My Heritage is easy to use,but the match base is small and every match has the same people on their matches...
                        I am still confused about the CM,Longest block and segments to filter out
                        Matches and have asked for help.All the info show how people match to their parents and close relatives.Not one shows figuring out others.Each site has differing amts.I am not looking for friends.I want to know a common ancestor and ethnicity that Imhave uncovered on each site.These maps are all different,so North Africa goes all the way to Cyprus...on one.
                        These companies are making big bucks but consumers are unaware about all the cons and work involved.People do not upload so much.Ged Match is great but the Oracles need a PHD interpretation.For the average person it could take a year to figure it out.I also have had matches respond one time.
                        Never had one contact me! I feel like I am being seen as an intruder into someone’s,personal life.So many matches are private without trees.if I mention the Cms and kit numbers they are deer in the headlights.This whole journey has not been pleasant.I wish there was someone out there in cyberspace that could teach the calculations easier.
                        I do not know my second ethnicity.It could be Sicilian or Maltese,even Turkish and I will never know.I know I have Sephardic and someone gave me matches.None ever replies...

                        .

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                        • #13
                          No one ever replies. Everyone is too ignorant. I've been trying to use DNA to break down 2 brick walls - 4 missing 3rd great-grandparents since 2010.

                          We can blame Ancestry for taking autosomal DNA testing, which started out as a serious tool for genealogists, and turning it into a big joke, making big profits for silly ethnicity reports, that their gullible customers will never know are highly questionable.

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                          • #14
                            [QUOTE=Miamio;448273]
                            I started out with FTDNA.Uploaed to Gene Cove,DNALand ,MyHeritage,Geni.Gedcom Genesis,Gene Plaza and Living DNA.
                            It sounds like you've thrown a lot of money at your project.

                            I am still confused about the CM,Longest block and segments to filter out
                            Matches and have asked for help.All the info show how people match to their parents and close relatives.Not one shows figuring out others.Each site has differing amts.I am not looking for friends.I want to know a common ancestor and ethnicity that Imhave uncovered on each site.These maps are all different,so North Africa goes all the way to Cyprus...on one.
                            Try reading Roberta Estes's blog. (Just Google her name.) That might help you to understand the basics of genetic genealogy.

                            These companies are making big bucks but consumers are unaware about all the cons and work involved.People do not upload so much.Ged Match is great but the Oracles need a PHD interpretation.For the average person it could take a year to figure it out.I also have had matches respond one time.
                            Never had one contact me!
                            People are human. Not everyone will be nice or cooperative. Many or most people won't. Get used to it.

                            I feel like I am being seen as an intruder into someone’s,personal life.So many matches are private without trees.
                            Many people, particularly on Ancestry, have locked their posted trees. Why? Because others confiscate their trees, using and replicating them with no other effort on their part. Ancestry has become mostly a big 'cut & paste' pastime for many there.

                            if I mention the Cms and kit numbers they are deer in the headlights.This whole journey has not been pleasant.I wish there was someone out there in cyberspace that could teach the calculations easier.
                            Read Roberta Estes's explanations and try to educate yourself. You don't need to become an expert at this. You only need to start understanding how genetic genealogy works.

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