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  • Hidden X MTDNA ?

    I have been doing family research on my mom's dad side. I found out he was not Irish but Scottish. A 7TH generation cousin e-mailed me with this information: Can you have a x gene that hides a bad gene?
    Quote:
    Another interesting fact is that the Hopewell ship did indeed have Ulster Scots. There is a rare form of genetic diabetes in the Ulster Scots and that condition was brought to Nova Scotia. This rare form is so rare that in a general population it is 4 in 10000 but in Nova Scotia this condition is in 24 in 1000. 10 times higher because of the Hopewell Ulster scots.
    Quote:
    It is a defect of the X chromosome, not the Y chromosome. This is why females rarely show the disease as they can have the defective gene but have a good X gene to hide the defect. The result is any male children she has 50 percent would have diabetes, the other 50 percent would be normal. The defect would have come from a female passenger that was a carrier.
    If a passenger that was on the hopewell had the defect that personwould not have made it to Nova Scotia. In those days water was limited. A person with this condition has to drink 20 litres of water a day.

    This has me curious.

    Pamela
    mtDNA K1a1b1a

  • #2
    The X chromosome (found in the nucleus of the cell) is different than mtDNA (found outside the nucleus).

    Females have two X chromosomes and males have an X and a Y. If a female inherits a copy of the mutated gene, her other X chromosome can still function and compensate for the defect. She would be a "carrier" -- and each of her children would have a 50% chance of inheriting an X chromosome harboring the mutation.

    The condition is diabetes insipidus (not the same thing as "sugar" diabetes). There is indeed a founder effect, with some patients tracing their ancestry back to the Hopewell, but different mutations in the same gene have been found in other populations.

    http://www.ndif.org/public/articles/...o_RFLP_Studies

    Comment


    • #3
      There is lot of confusion in the US about who is Irish and who it Scottish. Here are the reasons for most of the confusion:

      1) The island of Ireland is a divided nation Northern Ireland Presbyterian with Scottish ancestry and rest or Ireland Irish Catholic.
      2) The Northern Ireland Presbyterians are called Ulster Scots in Europe but in the US they are call Scotch-Irish. Not sure the name used in Canada.
      3) Add the US census where many Ulster Scots were listed as born in Ireland and some listing Scotland. I would suspect it would be the same in Canada.

      I would not get excited about known Irish ancestry being Scottish. They could still be Irish depending how you define the people.
      thetick
      FTDNA Customer
      Last edited by thetick; 16 March 2012, 06:21 PM.

      Comment


      • #4
        Hi Ann

        What is the condition " diabetes insipidus" ? I had my medical implications done. Even if the results show that I have none, can I still have the bad gene?
        Also how does the bad x mutation gene get started? Is it just a fluke?

        Pamela

        Comment


        • #5
          Pamela based on your name as a female you have two X pairs of DNA data while males only have one. So in the case of the X a trait/disease or not can be "hidden" or passed to the next generation without the mother exhibiting the trait. This is reason why red/green colorblindness is much more common with boys than girls.

          Comment


          • #6
            Originally posted by pamelaw View Post
            Hi Ann

            What is the condition " diabetes insipidus" ? I had my medical implications done. Even if the results show that I have none, can I still have the bad gene?
            Also how does the bad x mutation gene get started? Is it just a fluke?

            Pamela
            Here's the link to the Wikipedia article about diabetes insipidus:

            http://en.wikipedia.org/wiki/Diabetes_insipidus

            I assume you're talking about medical implications of your mtDNA. That is entirely separate from the X chromosome, where the mutation causing diabetes insipidus is found. The original mutation is indeed just a fluke -- the DNA copying enzymes aren't 100% perfect, and sometimes they just make a mistake. Most of the time, these mistakes are harmless, but once in a while they cause problems.

            Comment


            • #7
              Originally posted by thetick View Post
              Pamela based on your name as a female you have two X pairs of DNA data while males only have one. So in the case of the X a trait/disease or not can be "hidden" or passed to the next generation without the mother exhibiting the trait. This is reason why red/green colorblindness is much more common with boys than girls.

              I am confused? How can I get a x from my mom's dad's gene. I thought you could only get from my dad a x and my mom a x?

              Sorry to be so confused.

              Pamela

              Comment


              • #8
                Originally posted by pamelaw View Post
                I am confused? How can I get a x from my mom's dad's gene. I thought you could only get from my dad a x and my mom a x?

                Sorry to be so confused.

                Pamela
                See the short video http://www.smgf.org/education/animat...hromosome.jspx
                Take a look at the charts at http://www.thegeneticgenealogist.com...omosome-charts

                So as a female the percentage of X from:
                Paternal Grandfather 0%
                Paternal Grandmother 50%
                Maternal Grandfather 25%
                Maternal Grandmother 25%

                So the above shows you get one X uncombined from your father and the other combined from grandparents from your mother.
                thetick
                FTDNA Customer
                Last edited by thetick; 17 March 2012, 12:16 AM.

                Comment


                • #9
                  So I'm trying to understand this concept. I am a female so obviously XX. The X I received from my mother is a combination of both her parents,and further back, however the X I received from my father is an exact copy of the X he received from his mother? I would have thought that the X from him would have some combination of BOTH my paternal grandparents?

                  Comment


                  • #10
                    I think I understand better now, I checked out the link that the thetick gave, thanks Tick! And also saw about autosomal DNA (so this is where my paternal grandfather would contribute) and after pausing the inheritance patterns a few times I now get it! I think! I'm new to all this and I learned something new tonight about the X you receive from your father if you are female, I did not realize the inheritance pattern with it. Cool!

                    Comment


                    • #11
                      Originally posted by thetick View Post
                      See the short video http://www.smgf.org/education/animat...hromosome.jspx
                      Take a look at the charts at http://www.thegeneticgenealogist.com...omosome-charts

                      So as a female the percentage of X from:
                      Paternal Grandfather 0%
                      Paternal Grandmother 50%
                      Maternal Grandfather 25%
                      Maternal Grandmother 25%

                      So the above shows you get one X uncombined from your father and the other combined from grandparents from your mother.
                      Thank you! This will help me so much better to understand things!

                      Comment


                      • #12
                        Originally posted by pamelaw View Post
                        Thank you! This will help me so much better to understand things!
                        Great!
                        Yea SMGF videos and the X charts really are pictures worth a 1000 words. I tried in the past to explain the X in words and it's never ever successful.

                        Comment


                        • #13
                          Originally posted by thetick View Post
                          Great!
                          Yea SMGF videos and the X charts really are pictures worth a 1000 words. I tried in the past to explain the X in words and it's never ever successful.
                          I am more of a visual person! Thanks again.

                          Comment

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