Dear Fran, I am not sure I entirely understand your question. Your brother's X came from his mother. If he is matching with the 2nd cousin on the X then it is very likely that portion of his X came from his maternal grandmother. However, you can't tell at this point whether the segment came from the maternal great grandmother or from the maternal great grandfather. I don't know what your father has to do with this situation. As you probably realize, you got one of your X chromosomes from your father and one from your mother. If this doesn't answer your question, perhaps you can explain your question in greater detail. Sincerely, Tim Janzen -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Fran Meng Sent: Wednesday, November 16, 2011 8:42 PM To: [email protected] Subject: [AUTOSOMAL-DNA] Base Pairs With Full Match My brother shares on the X base pairs with a full match with several people including our second cousin. Our maternal grandmothers were sisters. Should I conclude that 1/2 is from our mothers and the other 1/2 is from our fathers?Could our fathers also be related? Fran [email protected] ------------------------------- 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