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I had my DNA done and a person popped up that I never heard of ..The total Autosomal 116.4, the largest cM is 50.3 But where I am stuck is on the X-DNA with the cM being 15.1.

Does the X-DNA match indicate we are related from the mother (maternal side)?


The Gedmatch kit in question Shirley R. (F) A573596 and THE OTHER KIT IS Debbie A. A344526...

We are trying to determine where we should began to look. All of our parents are deceased.

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    Possible duplicate of Interpreting X DNA? – lkessler Dec 20 '17 at 18:51
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    Hi, welcome to G&FH.SE! This question would be less cumbersome to answer if we knew the sex of both people whose kits are being compared. I agree with the previous comment that the answers of genealogy.stackexchange.com/questions/9350/interpreting-x-dna should help you answer this question -- if not, please clarify the total amount of shared DNA and the length of the shared segments, and tell us why you are still confused. You can use the edit link under your question to add more information. – Jan Murphy Dec 20 '17 at 20:56
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    I've edited the title of your question so it will be a question. You can learn more about how the site works in the help center and by taking the tour. – Jan Murphy Dec 20 '17 at 20:58
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You've indicated that both people are females.

Females get two X chromosomes: one from their mother and one from their father.

Males have one X chromosome, which they get from their mother.

So that X chromosome segment could have come from your mother's sides or from your father's mother's side, but not on your father's father's side.

That logic can also be carried back to further generations which could eliminate some ancestors from the ones who could have passed down that X segment.

However, X segments tend to be passed down more generations than other segments because males get the full chromosome from their mother. Therefore (as George Gaál pointed out in the comments), the X may come from a different ancestor than the majority of the other autosomal segments came from.

  • "So both of you might be related on your mother's sides or on your father's mother's side, but not on your father's father's side." This statement is incorect – George Gaál Dec 23 '17 at 19:09
  • @George - why is that incorrect? And if so, what would the correct statement be? Would it have been better to say that neither of you can be related through either of your father's father's side, but you can be related through your other three grandparents? – lkessler Dec 23 '17 at 23:57
  • because the size of matching X chromosome matters. So generally, X Match means nothing: nor you have relation via maternal line, nor you have not relation at all. For example, I have X Matches. I am man. And autosomal comparison shows that this matches come from paternal side. It is totally non-logical, because I've got X from my mother and she is not related to my father in any way (in historical timeframe). Also there are different situations like relationship between parents. So things become more complicated. This is why I don't trust X match at all – George Gaál Dec 24 '17 at 19:59
  • One needs additional processong of data to extract reliable information from X Match. There are great answers here : genealogy.stackexchange.com/questions/9350/interpreting-x-dna but I believe that they can be extended – George Gaál Dec 24 '17 at 20:00
  • @George - Thanks. I'll adjust my answer to only refer to where the X chromosome came from. – lkessler Dec 24 '17 at 21:39

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