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  • Autosomal/Y-DNA Match Possible Relative?

    I did post a thread concerning the Y-DNA portion of this question in the Y-DNA forum area and that was well answered. You can find that here.

    I'm still at a bit of a loss concerning the autosomal results and could use some advice.

    Basically my questions is:

    What is the likelihood that I am related to a person with whom I have a 35/37 Y-DNA match and a 10% autosomal match?

    Thanks in Advance.
    Last edited by limbicognito; 11 January 2012, 01:41 AM. Reason: Simplification

  • #2
    It is absolutely the case that you are related to a person with whom you share 10% autosomal identity. As per the Y data, it seems entirely possible that your relationship to the other can be on your paternal lines.

    A paternal uncle would share about 25% with you and a cousin, his son, would share about 12.5%. These percentages are averages, you could share anything from 0% to 50% with an uncle and anywhere from 0% to 25% with a cousin.

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    • #3
      Originally posted by tomcat View Post
      A paternal uncle would share about 25% with you and a cousin, his son, would share about 12.5%. These percentages are averages, you could share anything from 0% to 50% with an uncle and anywhere from 0% to 25% with a cousin.
      Thanks for your answer. I was lead to believe an uncle had to be around 25% and that 10% would mean that the uncle would have one different parent from an alleged father.

      I've not read anywhere else that an uncle can be 0-50%. I've read of 25% +/-5%. Are you sure?

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      • #4
        Originally posted by limbicognito View Post
        Thanks for your answer. I was lead to believe an uncle had to be around 25% and that 10% would mean that the uncle would have one different parent from an alleged father.

        I've not read anywhere else that an uncle can be 0-50%. I've read of 25% +/-5%. Are you sure?
        Following your Y-DNA post, looked like your connection could be a half uncle? That would fit.

        Linda

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        • #5
          Originally posted by limbicognito View Post
          I've not read anywhere else that an uncle can be 0-50%. I've read of 25% +/-5%. Are you sure?
          Yes.

          The range of potential shared identity for full siblings is 0% to 100%. At 0% they each would have received entirely different autosomal chromosomes from each parent. At 100% they would have received exactly the same autosomal chromosomes from each parent. Most siblings average 50% shared identity.

          Among my four sibling profiles the sharing range between siblings is 50.5% on the high end to 44.3% on the low end, a 6.2 point spread, or more than 10%.

          If your match is your paternal uncle, he would have shared identity with your father as per above, on average.

          In any event your match is close enough in genealogical time for you to discover the genealogical relationship.
          Last edited by tomcat; 11 January 2012, 05:33 PM.

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          • #6
            Where did you get 10%? From Relative Finder?... or from calculations you made on Family Finder's sum cM match? Please specify your given prediction by your autosomal test results and which company.

            Thanks,

            Matt.

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            • #7
              Originally posted by mkdexter View Post
              Where did you get 10%? From Relative Finder?... or from calculations you made on Family Finder's sum cM match? Please specify your given prediction by your autosomal test results and which company.
              Thanks everyone for your replies.

              First of all there is no paper trail whatsoever to make any connection between me, my known family and this individual and I've never met them or been in direct contact with them.

              Secondly whilst I have done a Y-DNA test with FTDNA. The autosomal matching was done by another company that provided a table of 20 autosomes.

              They tested the same 20 autosomes for both of us and there were 2 matches, thus the 10%.

              I'm still getting conflicting information and most of it is coming from this thread and the previous thread I posted in the Y-DNA forum.

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              • #8
                Originally posted by tomcat View Post
                In any event your match is close enough in genealogical time for you to discover the genealogical relationship.
                Care to expand upon that?

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                • #9
                  Originally posted by limbicognito View Post
                  They tested the same 20 autosomes for both of us and there were 2 matches, thus the 10%.

                  I'm still getting conflicting information and most of it is coming from this thread and the previous thread I posted in the Y-DNA forum.
                  Without more information on your autosomal test then my suggestion is simply that you may want to focus more on your 35/37 yDNA match and look at other yDNA match for similarities in names and things like that.

                  The conflicting information might be due to not knowing enough about what autosomal test you took. Two out of 20 autosomes sounds more like a STR based test and if so that would not indicate anything like a 10% shared quantity of autosomal DNA. I don't know for sure since you didn't mention the test name.

                  Matt.

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                  • #10
                    Originally posted by mkdexter View Post
                    The conflicting information might be due to not knowing enough about what autosomal test you took. Two out of 20 autosomes sounds more like a STR based test and if so that would not indicate anything like a 10% shared quantity of autosomal DNA. I don't know for sure since you didn't mention the test name.
                    Sorry I don't know much about autosomal testing and assumed it was all STR based. In my case it was STR based testing.

                    Would you be able to tell me what kind of relationship I can infer from a 2/20 STR based test match?

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                    • #11
                      Originally posted by mkdexter View Post
                      Without more information on your autosomal test then my suggestion is simply that you may want to focus more on your 35/37 yDNA match and look at other yDNA match for similarities in names and things like that.
                      Unfortunately in my case my surname has nothing to do with my biology, so I'm not sure that will help.
                      Last edited by limbicognito; 12 January 2012, 01:18 AM.

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                      • #12
                        Siblings could in theory be 0% to 100%. First cousins could in theory be 0% to 50%. But the average for siblings is 50% & the average for 1st cousins is 12.5%. The outliers at either end of the spectrum are extremely rare, so rare that it makes more sense to me to describe siblings as about 50% plus or minus, and so forth.

                        How many cases do we know of where full siblings have shared less than 40% or more than 60%? I'm sure there are abundant examples, but they nonetheless comprise a minority.

                        Timothy Peterman

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                        • #13
                          Originally posted by limbicognito View Post
                          Secondly whilst I have done a Y-DNA test with FTDNA. The autosomal matching was done by another company that provided a table of 20 autosomes.

                          They tested the same 20 autosomes for both of us and there were 2 matches, thus the 10%.
                          Oh, dear -- there's been a major misunderstanding here. Everyone assumed you were talking about the Family Finder test here at FTDNA, which is based on 700,000 autosomal SNPs.

                          The type of test you took was based on STRs. It makes a very good paternity test (where one of the child's alleles must come from the father for every single marker), but it is not very robust for more distant relationships. You could very well match virtually anyone at 2/20 autosomal STRs.

                          That puts you back at thinking about the 35/37 Y-STR results. The TMRCA can cover a very wide range for that level of match.

                          If you were motivated to take the paternity-type test because you had some reason to believe there was a connection, then it might be worthwhile to take the Family Finder test.
                          Last edited by Ann Turner; 12 January 2012, 08:28 AM.

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                          • #14
                            Originally posted by Ann Turner View Post
                            Oh, dear -- there's been a major misunderstanding here. Everyone assumed you were talking about the Family Finder test here at FTDNA, which is based on 700,000 autosomal SNPs.

                            The type of test you took was based on STRs. It makes a very good paternity test (where one of the child's alleles must come from the father for every single marker), but it is not very robust for more distant relationships. You could very well match virtually anyone at 2/20 autosomal STRs.

                            That puts you back at thinking about the 35/37 Y-STR results. The TMRCA can cover a very wide range for that level of match.

                            If you were motivated to take the paternity-type test because you had some reason to believe there was a connection, then it might be worthwhile to take the Family Finder test.
                            Hi Ann,

                            And thank you once more for your insightful contributions to both threads, much appreciated!

                            Sorry for the confusion, I guess I should have been very clear from the start. Unfortunately the original lab (not FTDNA) did not give much information at all about the results other than two pages one with STRs and the other with a 15-marker yDNA comparison.

                            Since then there have been new samples provided to FTDNA which is where I got the 35/37 y-match. I also have over 30 other Y-STR matches here at 23/25 and five different matches have the surname Potter... not sure how significant that is.

                            The reason that I have to believe that there is a match is because of a story that has been relayed to me by someone outside my family that a man (now deceased) was my biological father, his brother agreed to submit a sample for a test but I have never met him as he lives in another state.

                            Just to be clear about the autosomal STR results, if there is a comparison for instance like this:

                            D19S433
                            Person A: 12,14
                            Person B: 12,13

                            Does the first 12 that each person have count as a match or do both have to be identical?

                            Thanks again.
                            Last edited by limbicognito; 12 January 2012, 08:58 AM.

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                            • #15
                              Originally posted by limbicognito View Post
                              Just to be clear about the autosomal STR results, if there is a comparison for instance like this:

                              D19S433
                              Person A: 12,14
                              Person B: 12,13

                              Does the first 12 that each person have count as a match or do both have to be identical?

                              Thanks again.
                              You just need to match one of the alleles. One comes from the father and the other from the mother, but we don't know which is which -- just that both alleles were in the "soup." The alleles are customarily given in ascending order. If the results were

                              Person A: 12,14
                              Person B: 10,12

                              then the 12 allele would qualify as being present in both the child and the father. It might be an coincidental match, but coincidental matches are not likely to occur on every single marker.

                              From what you say, I think a Family Finder test would be useful. Even if it turns out negative, you will get information about other potential relatives.

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