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X chromosome ancestry testing: Selecting the right candidate

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  • #91
    Originally posted by DKF View Post
    ... The X is fascinating and the possibilities much more extensive than the Y. ...The problem, as I have been harping on for some time, is that people will need to forget about what is or is not on the autosomes and take the time to figure out percentages for each group relating only to the X. ...
    Neither Y genealogy nor the Y itself is relevant to X as the direct male line Y does not appear in X except for limited crossover in the telomeres. MtDNA does seem relevant to X as most of us are not so very far removed from historic populations that ought to have an Mt typology. And I can imagine how autosomal results could help resolve bio-geographical attributions on X. The X chromosome is golden for those family historians who have done the work to limn/limb their internal lines.

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    • #92
      Originally posted by Kathleen Carrow View Post
      ...
      I HAVE seen some people are not representing their X ancestry correctly and I guess all that can happen there is you discount what those people say their ethnicity is?...
      I think one is justified in attributing ancestry percentages to X based on parental ancestry. So, if one is personally 50/50 French and Spanish, the corresponding parental X's are 100% French and 100% Spanish. (Although the parental X's are only 50% of the picture, e.g. the father's X is only "half" of the X of his mother, but that "half" is still 100% of the ancestry of the mother).
      Last edited by tomcat; 24 February 2009, 12:04 PM.

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      • #93
        Originally posted by tomcat View Post
        Neither Y genealogy nor the Y itself is relevant to X as the direct male line Y does not appear in X except for limited crossover in the telomeres. MtDNA does seem relevant to X as most of us are not so very far removed from historic populations that ought to have an Mt typology. And I can imagine how autosomal results could help resolve bio-geographical attributions on X. The X chromosome is golden for those family historians who have done the work to limn/limb their internal lines.
        Yes, and some of it is just luck. I always had an "admiration" (some jealous envy I suppose) for those who followed the surname line down to the present from an ancestor who married a Mohawk (whose ancestors in turn I have traced 5 generations back to the mid 1600s). As it turns out they are about 8 meioses (recombination events) from our ancestor, and on the X chromosome thanks to zig zagging each generation (male, female, male etc.) my uncles are only 3 meioses removed (and I am 4). Hence, due to the quirky way that the X is transmitted from generation to generation my branch of the family is closest to our NA ancestor than any of the hundreds of others - who would have figured that one, not me until very very recently. So by happenstance every X in every cell carries 12.5% NA (this via direct analysis of the decodeme data - on paper I "should" be 6.25%). It is quite fascinating to see things in this light, it can change the perception of one's own identity. So for some the X is a Godsend - particularly now that we have decodeme and 23andme data that can be compared to the HGDP-CEPH worldwide panel (for example).

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        • #94
          DKF,
          Can I ask, is there a database that covers populations from all over the world regarding X testing?
          I am wondering if this would shed some light on Mum's unknown father's ancestry...even if it was within Europe, could his X Mum inheirited be matched to certain populations?
          Is this the same as DeCodeMe and 23andme's X painting?
          Sorry if this has been covered, but this whole area confuses me and it actually seems to me to have a bit more credibility than autosomal testing so I'm interested to find out more. Thanks.

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          • #95
            Originally posted by burto View Post
            DKF,
            Can I ask, is there a database that covers populations from all over the world regarding X testing?
            I am wondering if this would shed some light on Mum's unknown father's ancestry...even if it was within Europe, could his X Mum inheirited be matched to certain populations?
            Is this the same as DeCodeMe and 23andme's X painting?
            Sorry if this has been covered, but this whole area confuses me and it actually seems to me to have a bit more credibility than autosomal testing so I'm interested to find out more. Thanks.
            Burto,

            Alas we really only have the output of 23andme (via their Ancestry Painting which won't include the X until later this year) and decodeme via their browser and "Compare Me" to get a general sense of ancestry. As to specifics in relation to the X this would have to be done individually. I had the assistance of someone who took it upon himself to become familiar with sophisticated programmes such as PLINK, SABER, and PHASE as well as Excel formulae to search for matches using the HapMap or HGDP-CEPH databases (freely available online). But, frankly, without the assistance of Anders with my case study (to compare a known minority genealogy and predicted percentage on the the X to worldwide databases), I would have been entirely lost. It would taken months of dedicated trial and error effort (plus the need for requisite computing skills) to mimic what Anders has been able to accomplish. I know that 23andme has plans to offer something along these lines, which will be "phased in" over the next few months to a year.

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            • #96
              Originally posted by burto View Post
              ... is there a database that covers populations from all over the world regarding X testing?
              I am wondering if this would shed some light on Mum's unknown father's ancestry...even if it was within Europe, could his X Mum inheirited be matched to certain populations?
              Is this the same as DeCodeMe and 23andme's X painting?...
              If your mother did 23andMe she could get ancestry estimates for 22 autosomal chromosomes and the semi-autosomal X now, but only the 22 autosomal chromosome would be covered in Ancestry Painting (you can apply for a trial memebership at 23andMe to sample features). If she did DeCodeMe all chromosomes would be covered by all analytic features now (you can also sample DeCodeMe features at their site).

              All ancestry estimates are based on HGDP-CEPH database that covers a limited number of world populations. (You can Google it to see if the populations covered are appropriate to your interests). The more ethnically distinct your mother's parents were, the more distinct her results; if they were both European, her 23andMe chromosome painting would just be colored European or her DeCodeMe results would get high scores for similarity to Europeans. Both 23andMe and DeCodeMe only parse results into European, East Asian and African. Native American is assumed to be equivalent to East Asian.
              Last edited by tomcat; 26 February 2009, 12:35 PM.

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              • #97
                Sister's markers and signature

                Although the signature change may seem fancy the point here is that as I received back the rest of Sister's X markers and added them to the World Forums X STR table I realized that I had not really identified my X populations.

                So I went back and used the largest table available to me and realized that my Swedish ancestry, although real, is not reflected in my X markers. My Swedish Great Grandfather's MOTHER is who I get my X inheritance from..so the Swedes drop off of this as does the Germans.

                I am left with mostly Irish and a lot of Early Colonial folks whose names I know but country of Origin I do not. Mostly it seems, due to their whereabouts, religious preferences and marital preferences they are Irish,Welsh, English.

                Colonial Delaware is more mysterious than most having wafted through Swedish and English dominance with old population staying put and assimilating as the new folks came in.

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                • #98
                  Originally posted by tomcat View Post
                  If your mother did 23andMe she could get ancestry estimates for 22 autosomal chromosomes and the semi-autosomal X now, but only the 22 autosomal chromosome would be covered in Ancestry Painting ...
                  Correction: 23andMe is absolutely silent on X, at present, as to ancestry. I don't know if X figures in their disease database.

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