Dear Tim, To hopefully clarify my question, I meant from my paternal grandmother's X which to me meant my father's family. Could you please explain your answer? Do you mean my brother is only receiving his X from our mother and nothing from our father's mother? My brother and I only share 1/2 base pair on our X. My paternal uncle and I share several long blocks on our X,some are 1/2 and others have green stripes [full]. Is this just coming from my paternal grandmother and not my paternal grandfather's mother? Which grandmothers contribute to our combined ch. X? From your answer I'm assuming that my brother can only receive his from our mother because he is XY but I can receive it from both of my grandmothers since I'm XX. Could you please explain to me how this works? We were tested by Family Tree dna and our ch.X results were not given to us. Thanks. Fran

Dear Fran, Your brother got his Y chromosome from his father and his X chromosome from his mother. It always happens that way unless there is some unusual genetic abnormality such as Klinefelter's syndrome (XXY), or some other situation in which a male gets more than 2 sex chromosomes. Females get one X chromosome from their father and one X chromosome from their mother, unless there is some unusual genetic abnormality such as Turner's syndrome (X). Your brother thus only matches you on one of your X chromosomes. The matching blocks on the X that you share with your paternal uncle are likely coming from your paternal grandmother since your uncle received his X chromosome from your paternal grandmother. Your brother should not be sharing any large segments on the X with his paternal uncle. To better understand how the X chromosome is inherited I would suggest that you review the charts at http://www.thegeneticgenealogist.com/2008/12/21/unlocking-the-genealogical-s ecrets-of-the-x-chromosome/. Sincerely, Tim Janzen -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Frances Meng Sent: Thursday, November 17, 2011 7:19 AM To: [email protected] Subject: [AUTOSOMAL-DNA] Base Pair With Full Match Dear Tim, To hopefully clarify my question, I meant from my paternal grandmother's X which to me meant my father's family. Could you please explain your answer? Do you mean my brother is only receiving his X from our mother and nothing from our father's mother? My brother and I only share 1/2 base pair on our X. My paternal uncle and I share several long blocks on our X,some are 1/2 and others have green stripes [full]. Is this just coming from my paternal grandmother and not my paternal grandfather's mother? Which grandmothers contribute to our combined ch. X? From your answer I'm assuming that my brother can only receive his from our mother because he is XY but I can receive it from both of my grandmothers since I'm XX. Could you please explain to me how this works? We were tested by Family Tree dna and our ch.X results were not given to us. Thanks. Fran

Hi Fran A sister gets an X form each of her parents. A brother would only get an X only from his Mum. The X a brother would inherit from his Mother initially has come form her parents [so half the material of the mothers x has come from the maternal grandfather and half from maternal grandmother] While the sister's X [X from her father has come from her paternal grandmother and from her mother's x has come from both her maternal grandfather and from her maternal grandmother ] Essentially as you go back the parts of the X are being mixed up with mixes of DNA coming down the female side. A son passes his X once to his son but that son pass on his mothers x A daughter passes her X to both sons and daughters. The son passes it once but only to his son. The daughters continue to pass the Mother's x down the generations [becoming less with each generation] until it disappears having been replaced by more recent generations X material. Karen Karen On Fri, Nov 18, 2011 at 2:18 AM, Frances Meng <[email protected]> wrote: > Dear Tim, > > To hopefully clarify my question, I meant from my paternal grandmother's X which to me meant my father's family. Could you please explain your answer? Do you mean my brother is only receiving his X from our mother and nothing from our father's mother? My brother and I only share 1/2 base pair on our X. > > My paternal uncle and I share several long blocks on our X,some are 1/2 and others have green stripes [full]. Is this just coming from my paternal grandmother and not my paternal grandfather's mother? > > Which grandmothers contribute to our combined ch. X? From your answer I'm assuming that my brother can only receive his from our mother because he is XY but I can receive it from both of my grandmothers since I'm XX. > > Could you please explain to me how this works? We were tested by Family Tree dna and our ch.X results were not given to us. > > Thanks. > Fran > > > ------------------------------- > To unsubscribe from the list, please send an email to [email protected] with the word 'unsubscribe' without the quotes in the subject and the body of the message >