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the "X" girls get from Dad

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  • #16
    Human females contain two X chromosomes, and males contain one X and one Y
    chromosome. In the absence of a Y chromosome, a human fetus will develop as a female.
    This indicates that a gene or genes on the Y chromosome determines "maleness". Several
    genes that are required for male development have been located on the Y chromosome, but
    as far as I know, the "master" gene has not yet been identified.

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    • #17
      more questions on the X from dad

      Originally posted by tomcat View Post
      Gene tests sample the autosome and so sample both X in females. Sisters would have an X in common that is the X that came from their common father and is unchanged from the X their common paternal grandmother bequeathed to their common father. The other X, from their common mother, would vary as it is a one-of-a-kind product of recombination.
      This is my first reply on any blog and I am new to the concept of DNA for genealogy purposes, but I have three questions.

      One is: if the DNA lab analyzes both of a female

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      • #18
        more Q's on the x from dad, attempt 2

        This is my first reply on any blog and I am new to the concept of DNA for genealogy purposes, but I have three questions.

        One is: if the DNA lab analyzes both of a female

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        • #19
          23andMe will provide both results, but there is no way to know which came from your mother and which came from your father without testing one of them as well.

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          • #20
            those 2 x's

            Thanks How many companies analyze mtDNA by the way?

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            • #21
              ^ I believe affordable mtDNA testing for genealogical purposes has been around longer than affordable Y-DNA testing so I guess if Y testing is offered, mtDNA will be also.

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              • #22
                Originally posted by rucksack View Post
                23andMe will provide both results, but there is no way to know which came from your mother and which came from your father without testing one of them as well.
                Or testing a brother, who got a single version of X from Mom that will contrast with the unvarying X all daughters got from Dad. Then test as many other siblings as possible to capture the balance of Mom's two X's.

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                • #23
                  X from Dad and X from Mom

                  After perusing a couple threads, I think I know what happened to my previous attempts with questions. So I will try to avoid symbols and punctuation.

                  If I order mtDNA, is the analysis of one X or both? I am a female adoptee. I know pretty much the ancestry of my birthmother, but not much about my birthfather. My birthmother thought my birthfather's mother had a strong accent. Would that ancestry show up in an analysis?

                  Do all companies give a percentage for nationality? If not all, which ones do? Or would a different kind of result be available and more helpful? Would that percentage be for me or for one of my two Xs?

                  How many companies are there out there that do mtDNA analysis? I am completely new to this whole idea.

                  Many thanks.

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                  • #24
                    FTDNA offers two panels of X STR's, but I recommend 23andMe or DeCodeMe, the genome scanners, who cover thousands of X SNP's. Both FTDNA and the scanners would sequence both your X chromosomes.

                    Both scanners offer percentage ancestry estimates. 23andMe estimates percentages of European, African and Asian ancestry for the 22 autosomes (not X yet). DeCode does ancestry estimates that include X.

                    Each of your birth parents would have to descend, to a significant degree, from distinct ancestries in order for them to appear distinct in scanner graphics. However, you need not depend solely on 23andMe or DeCode analyses, as there are folks who do follow-on analyses of raw data files (for X, Y, and autosomal).

                    The scanners include assortments of SNP's from Mt, but I judge FTDNA's Mt results more thorough and reliable. Mt is different than X. Mt descends solely through the mother and is not subject to recombination. X descends through both parental lines and is subject to recombination in females.
                    Last edited by tomcat; 9 October 2009, 12:06 PM.

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                    • #25
                      Thanks for the info.

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