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General => Ancestral Family Tree DNA Testing => Topic started by: Annie65115 on Wednesday 19 October 16 13:12 BST (UK)
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I have a moderately distant (prob 150 - 200 yr ago) match with 3 living members of the same family; 2 men and a woman.
All 3 match with me for a decent stretch on chromosome 5. However only the female shares an X c'some match with me as well.
Does this signify that our match is from their paternal line, or not?
<<<confused>>>
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Sorry I am no help but, the whole X thing confuses me too. I've read lots about it but nothing seems to clarify whether X links are worth investigating. I always think scientists are vague and use lots of gobbledegook language when they aren't quite sure themselves :-)
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Assuming you are a female.....you receive an X chromosome from each of your parents.
Your mother received her X chromosomes from each of her parents. Your father received his single X chromosome from his mother . And so it goes.
There is a specific inheritance pattern for the X chromosome. You can create an X-tree starting with yourself and working back those 150 to 200 years. Your father's father will not be in it neither will your maternal grandfather's father. The X chromosome is not passed from male to male so all those lines are removed going backwards.
If you have all the relationships going back all those years and the other person does as well, you will be able to find the common ancestor.
This inheritance diagram is included on the following blog by Louise Coakley and includes a downloadable template.
http://www.genie1.com.au/blog/63-x-dna
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I kinda get that bit Spike but, and, sorry Annie for hyjacking your post, what I don't get is if I have relatively small overall link with someone on Gedmatch, just 7+ but, a relatively high X match 30+ does the X match mean anything? I also have some fairly high X matches with 0 general matches, is that a match of any sort?
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I kinda get that bit Spike but, and, sorry Annie for hyjacking your post, what I don't get is if I have relatively small overall link with someone on Gedmatch, just 7+ but, a relatively high X match 30+ does the X match mean anything? I also have some fairly high X matches with 0 general matches, is that a match of any sort?
If that person is a man you match on their mothers side. If you are both female then you can narrow down the match to lines in the diagram above.
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Unless it's a whopping great big matching segment I'd not make any assumptions about which side it is from. 30cM is quite large, so it may well be a maternal match.
A couple of kits I manage (females) match several 3rd cousins who are 3rd cousins via their paternal grandfather. The only X-DNA these females would have received from their paternal side had to come from their paternal grandmother, NOT the paternal grandfather.
However they share some smallish segments of X-DNA with a couple of these 3rd cousins. So, somehow, there is some other relationship between them as well.
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I have a nearly-30cm-segment on the X c'some with a man with whom I have confirmed our shared ancestry, and I rather like the idea that that bit of my DNA comes from my ancestor Rebecca :)
(it has to be from her since we both have it, he's a man, and we're both descended from her - she is our shared ancestor, and as can be seen from the charts above, he could ONLY have inherited it from her, not from her husband).
But this other link, about whom I started this thread, is about a different sequence on the X and a different family and the more I think about it, the more I think that its absence on the males on this family means nothing in terms of where it came from. I think that segments on the X chromosone, when present, can help (as in my ancestor Rebecca) but their absence doesn't mean a thing.
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But this other link, about whom I started this thread, is about a different sequence on the X and a different family and the more I think about it, the more I think that its absence on the males on this family means nothing in terms of where it came from. I think that segments on the X chromosone, when present, can help (as in my ancestor Rebecca) but their absence doesn't mean a thing.
Annie, it is quite rare for males to have X-chr matches, so I think you are correct in what you are saying. I have only three matches, but one is with another male and it is a somewhat astonishing 40cM's. I sent my X inheritance names off to his admin and found that we both matched to my great grandmother's father's mother bpt 1807. From there it was a doddle to confirm the relationship on paper.
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Unless it's a whopping great big matching segment I'd not make any assumptions about which side it is from. 30cM is quite large, so it may well be a maternal match.
As a DNA newbie, I'd be interested to know how big a segment has to be to be considered a "whopping great big one" (I know that sounds silly but it's a genuine question!)
ta :)
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A question may seem sillyto experts Annie ..but alwys.helps those who are afraid to ask
people on here have a wonderful way of putting things simply look forward to hearing the answer
it sounds like an algebra problem to me
" if X x ? = Whopping great
what is the possibility of Her matching him "
sorry if flippancy offends anyone
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Unless it's a whopping great big matching segment I'd not make any assumptions about which side it is from. 30cM is quite large, so it may well be a maternal match.
As a DNA newbie, I'd be interested to know how big a segment has to be to be considered a "whopping great big one" (I know that sounds silly but it's a genuine question!)
ta :)
We each get 50% of our DNA from each of our parents. But, we don't get 25% from each of our grandparents. Our parents recombine each of their given chromosomes before they pass them on to their children. There is a randomness about this, and no two siblings (except for identical twins) get exactly the same DNA from their parents. Each chromosome recombines either once, twice or three times. Four lots of recombination would be rare as would be a zero recombination, ie the chromosome being handed down intact.
If you did get a chromosome intact from a grandparent, one could probably (if one must) describe that as a "whopping great big one". But other than that I don't think there is an exact definition. After all, and to keep with the flippancy theme, size is relative.
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As a DNA newbie, I'd be interested to know how big a segment has to be to be considered a "whopping great big one" (I know that sounds silly but it's a genuine question!)
ta :)
It's the next size up from "quite long". ;)
I've just been looking over at Gedmatch at some relatives' kits, but none of them should be X-matches (apart from some siblings).
For these kits (excluding the siblings) in a one-to-many X-chromosome search the longest X-matches for any of these kits is around 30cM. There's only two or three other kits with matching segments on the X as long as this.
Most of the X-matches are not autosomal matches.