Announcement

Collapse
No announcement yet.

X chromosome ancestry testing: Selecting the right candidate

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • tomcat
    replied
    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.

    Leave a comment:


  • Kathleen Carrow
    replied
    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.

    Leave a comment:


  • tomcat
    replied
    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.

    Leave a comment:


  • DKF
    replied
    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.

    Leave a comment:


  • burto
    replied
    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.

    Leave a comment:


  • DKF
    replied
    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).

    Leave a comment:


  • tomcat
    replied
    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.

    Leave a comment:


  • tomcat
    replied
    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.

    Leave a comment:


  • tomcat
    replied
    This study from last year on Latin America shows that older, Native American and African signals of admixture are better preserved on the X chromosome than in the autosome.

    http://www.plosgenetics.org/article/...l.pgen.1000037

    (And for those with DNATribes matches to 'Mestizo' populations the paper provides some guidance to degree of Native American ancestry in selected populations. Although that information is also available by Googling demographics for said populaions.)

    Leave a comment:


  • tomcat
    replied
    Originally posted by Kathleen Carrow View Post
    ... Of course my only REAL unknown IS the paternal Grandfather so maybe at some point autosomal SNPS might help to define that person? Full genome?
    I think autosomal markers are your only hope and the genome-wide scans are, at present, the most comprehensive autosomal assays. That grandfather accounts for one quarter of your autosome (nominally) so some contribution from him must certainly be present. The problem is discerning his contribution from that of the other three grandparents. That would be easier if he was ethnically different from the other three and the comparative database highlighted that ethnic difference.

    Leave a comment:


  • Kathleen Carrow
    replied
    Well for sure you are correct about the X ancestry..being quite different.
    I was surprised myself to see my percentages. I have forgotten sometimes and look for a hint of my paternal line there but I have it down now and it is not hard.

    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?

    Of course my only REAL unknown IS the paternal Grandfather so maybe at some point autosomal SNPS might help to define that person? Full genome?

    Leave a comment:


  • DKF
    replied
    Originally posted by Kathleen Carrow View Post
    Hi Everyone
    I was just informed that Family Tree DNA has lowered their X STR prices to be inline with the Y test..
    Panel #1 is now $99..
    Additionally they plan a Comparative Database for the X markers soon..possibly to be accessed from our Personal pages..
    Yeah for them~!
    Kathleen
    Pretty savy move on their part Kathleen.

    There must be a lot of customers such as myself who shouldered the burden for testing every cousin imaginable, as well as deep deep clade SNP testing for myself and select cousins, and have gone as far with this as is possible at this point.

    This will awaken many of us looking for new avenues to explore. The X is fascinating and the possibilities much more extensive than the Y. So yes, if Thomas migrates all of the data from the DNA-P database, then we will have a good running start.

    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.

    It is more complicated for females, and mind boggling going back beyond say 7 generations, but if people are putting down any data where for example a father's father is involved this data will be totally misleading and worse. It is so easy with the straight Y or mtDNA lines, but all of the cross over zig zagging but stopping here, but continuing there ....... But, once the task is done that is it, then interpretation and direct comparisons will be possible - but you will often have to trust that your match has done the task "by the numbers".

    Leave a comment:


  • Kathleen Carrow
    replied
    Originally posted by Kathleen Carrow View Post
    Hi Everyone
    I was just informed that Family Tree DNA has lowered their X STR prices to be inline with the Y test..
    Panel #1 is now $99..
    Additionally they plan a Comparative Database for the X markers soon..possibly to be accessed from our Personal pages..
    Yeah for them~!
    Kathleen

    Looking at this again I realzie that $99 is the price for "New Tests" if you have already tested at FTDNA the price for Panel #1 is $48.

    Leave a comment:


  • tomcat
    replied
    Good news!
    (If you've been waiting to do X STR's, now you know the reason why).
    Wonder if all of DNAF's Xmatch will move to the FTDNA X db?

    Leave a comment:


  • Kathleen Carrow
    replied
    New Prices and Services

    Hi Everyone
    I was just informed that Family Tree DNA has lowered their X STR prices to be inline with the Y test..
    Panel #1 is now $99..
    Additionally they plan a Comparative Database for the X markers soon..possibly to be accessed from our Personal pages..
    Yeah for them~!
    Kathleen

    Leave a comment:

Working...
X