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X chromosome ancestry testing: Selecting the right candidate

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  • JuanCarlos
    replied
    What I want to know is the following: If I order the X panel from FTDNA, in practical terms, what can I expect to learn? Also, once I receive the results, how do I decipher their meaning? Does FTDNA provide any interpretation, would I have to enter my results some place else in order to get some feedback? I still do not fully comprehend which ancestors I am supposed to have inherited their chromosomes, genes or whatever you call them, from, following the X chromosome ancestry testing. I have seen the graphs, but they still look confusing to me and I really don't like to think hard, that is the reason I come here to get the input of smarter people like Tomcat, DKF etc. etc. To me this whole X chromosome thing looks and reads like a puzzle.

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  • tomcat
    replied
    DKF,

    Perhaps you could post here some of the analytical projects one can accomplish with X SNP's. There are options through the labs but what are the options among the genetic genealogical testing community?

    Tom

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  • Kathleen Carrow
    replied
    Originally posted by Kathleen Carrow View Post
    For those of you who do not visit the Rootsweb DNA Genealogy list there is a great post from Jim Turner giving a link to forms that he apparently put together showing percentages of inheritance on X markers..

    Kudos to him!
    http://archiver.rootsweb.ancestry.co...-01/1231607913

    Here is a link just to the link that shows all of the forms
    http://freepages.genealogy.rootsweb....heritance.html

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  • Kathleen Carrow
    replied
    Check this out

    For those of you who do not visit the Rootsweb DNA Genealogy list there is a great post from Jim Turner giving a link to forms that he apparently put together showing percentages of inheritance on X markers..

    Kudos to him!
    http://archiver.rootsweb.ancestry.co...-01/1231607913

    Leave a comment:


  • tomcat
    replied
    Originally posted by Kathleen Carrow View Post
    ...IS 23andme all SNPS?
    I guess both together would be very informational but the STRs ( Haploblocks ) could be also if enough test...
    Which Tom Krahn had indicated travel in a block relatively unchanged for maybe 1000 years?
    Yes the genome scanners are all SNP testers. And some the X SNP's they test indicate X blocks that are in linkage disequilibrium (not subject to recombination) and one of those LD blocks covers the same area as the LD X STR's that FTDNA tests.

    SNP's are generally assumed to be unique event polymorphims (UEP's) that occurred only once. So, the X SNP's that differentiate Native Americans from Africans, for example, must have accumulated over dozens of millenia. Hence X SNP's are assumed to be very useful in establishing general ancestry to a good degree of certainty.

    X STR's, even if in linkage disequilibrium, are free to add or drop repeats. And while the clock rate for such germ line mutations is not established, it is assumed to be much more rapid than SNP mutation. So, when one combines X SNP LD blocks with X STR's within those blocks one ought to be able to get very fine grained detail on ancestry and/or information on more recent ancestry within the frame of general ancestry.

    Taking a lesson from Y testing, I don't know if LD X STR's would be enough to establish ancestry absent the SNP frame of reference. But certainly the two in combination would yield much more detailed information and a higher degree of certainty that ancestry-informative STR matches are not just chance.

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  • Kathleen Carrow
    replied
    Originally posted by MMaddi View Post
    The SNPs are tested by 23andMe. David and Tomcat were discussing how it might be possible to get more information about ancestors who contributed to their x chromosome by combining SNP testing from 23andMe and STR testing from FTDNA.
    Thanks for the information..did not have a clue
    IS 23andme all SNPS?
    I guess both together would be very informational but the STRs ( Haploblocks ) could be also if enough test..

    I mentioned this earlier but my J2b closest FGS match altho' his family did NOT match the haploblock, they ( his sisters) match my Sister and I on a lot of X markers..
    Which Tom Krahn had indicated travel in a block relatively unchanged for maybe 1000 years?

    Leave a comment:


  • MMaddi
    replied
    Originally posted by Kathleen Carrow View Post

    I don't understand..I have the Block with STRs? or do I have SNPS??
    DXS10074 = 8-15
    DXS10075 = 16-18
    DXS10079 = 16-18

    so my blocks are 8-18-18 AND 15-16-16 one form Dad and one from Mom but WHERE are my SNPS?
    Is that something I should have?
    The SNPs are tested by 23andMe. David and Tomcat were discussing how it might be possible to get more information about ancestors who contributed to their x chromosome by combining SNP testing from 23andMe and STR testing from FTDNA.

    Leave a comment:


  • Deirwha
    replied
    I am all ears also

    Oh, the error message tells me I must add 10 characters to my smile. Other than Colchaire and me I was at a loss to fill out this requirement.

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  • Kathleen Carrow
    replied
    Originally posted by tomcat View Post
    Was just thinking the same. The haploblock STR's could yield higher resolution. Although they are in an LD block they are not constrained from adding or dropping repeats. But you need a match on the block as defined by SNP's in order to make any sense of the STR repeat motifs.

    I don't understand..I have the Block with STRs? or do I have SNPS??
    DXS10074 = 8-15
    DXS10075 = 16-18
    DXS10079 = 16-18

    so my blocks are 8-18-18 AND 15-16-16 one form Dad and one from Mom but WHERE are my SNPS?
    Is that something I should have?

    Leave a comment:


  • tomcat
    replied
    Originally posted by DKF View Post
    ...Guess I better test these too. I know what my SNPs are in this region of the X. It would be interesting to also have the STRs from this area with high linkage disquilibrium (in other words the region is unlikely to be split by recombination) - although there is variability in this region so I will check on the level of cM/Mb in the specific area (the lower the better) and can be more specific in a later post.
    Was just thinking the same. The haploblock STR's could yield higher resolution. Although they are in an LD block they are not constrained from adding or dropping repeats. But you need a match on the block as defined by SNP's in order to make any sense of the STR repeat motifs.

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  • DKF
    replied
    Originally posted by tomcat View Post
    Is one lab preferrable to the other? Is DeCode sinking with the Icelandic economy? I know DeCode runs more SNP's. Is one service easier to use? What is DeCode's coverage of X compared to 23etMoi?
    Each has their advantages and disadvantages. The price factor is clearly in favor of 23andme, but to date they don't have a browser like that of decodeme to compare degree of matching between members of various population groups (for example).

    I think I will wait a bit and see if the latter brings down their price or the former develops more sophistocated tools to interpret the results. The Ancestry Painting is good, but mostly for novices happy with a "general idea" about things.

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  • DKF
    replied
    Originally posted by Kathleen Carrow View Post
    I have a close FGS match who has one extra mutation but we have an ancestral spot of our mtDNA ancestors of near Bantry Bay in Cork c. 1837-41.. we match on the Coding region exactly..His sisters and my sister and I share many many markers on our X profiles..
    however we do NOT share the X haploblock at DXS 10074-10075-10079 nor do we share the mini block at DXS 10066-67-68.

    I DO however share one of my X blocks with one person and the other one with another person.. he is currently testing another relative as am I..we have shared know names

    They are minimal in expense at FTDNA and are a good starting point and Thomas Krahn has that interactive database at DNA-FP..there are currently 518 users with datasets displayed there..(Which is free)

    If everyone who could not currently afford 23and me who has tested and has a sample at FTDA tested those markers it would be only about $50-60 with a free interactive database that has e-mails attached..

    But maybe I do not understand the relevance of the whole genome study?
    Many of us have done most of it in bits and pieces..
    FGS, Y lines for every ancestor we can find..X and at markers for siblings...
    I only have the one sister but I did my son who shares one block of course..
    Tom has done a PACK of siblings..bless him..

    all are welcome
    Here is a link to the original paper where these markers are analyzed:

    http://www.excli.de/vol6/Hering06-07proof.pdf

    Guess I better test these too. I know what my SNPs are in this region of the X. It would be interesting to also have the STRs from this area with high linkage disquilibrium (in other words the region is unlikely to be split by recombination) - although there is variability in this region so I will check on the level of cM/Mb in the specific area (the lower the better) and can be more specific in a later post.

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  • tomcat
    replied
    Originally posted by DKF View Post
    ...
    Hope you can find a way to get tested, I certainly do not regret a penny spent with decodeme and 23andme...
    Is one lab preferrable to the other? Is DeCode sinking with the Icelandic economy? I know DeCode runs more SNP's. Is one service easier to use? What is DeCode's coverage of X compared to 23etMoi?

    Leave a comment:


  • Deirwha
    replied
    Thanks

    I copied down those test numbers.

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  • Kathleen Carrow
    replied
    Originally posted by Deirwha
    Would you recommend those same blocks for me (or are there alternatives?)
    Thomas K. had said this:
    "Once we have a useful number of participants in our database, this will
    be without a doubt a helpful tool to explore heritage in a mixed
    male-female-male-female etc. line. So even if I don't want to make too
    much advertising on this list for my own company, I would strongly
    recommend to just test those three linked markers from the Szibor paper
    (DXS10074 / DXS10075 / DXS10079) for as many people as possible. I also
    recommend to connect our X haplotype observations with the male Y
    haplogroups, because if the paternal line comes from one region of the
    world, it is most likely, that the female partner will also come from
    the same geographical region. This would allow us to establish the X
    haplogroup map more quickly and the erroreous designations will soon be
    averaged out if the sample number increases."

    and there is an earlier thread here on the markers..
    "Testing DYX 10074-10075 and 10079" or something like that..he also told me the "Other " Haploblock was a lesser one ..
    if I find the quote from him on that one I will post that also..
    Kath

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