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Old 12-03-2014, 11:07 AM
 
Location: Atlanta
6,793 posts, read 5,661,715 times
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I have a double first cousin.

His dad and my mom are brother and sister.
His mom and my dad are brother and sister.

We have the exact same ancestry but not the same DNA. I was wondering how much more info I could get about my mom's side of the family if I had his DNA tested.

It seems like I get could some info from his Dad's Y DNA about my mom's side of the family that I could not other wise obtain...

make sense?
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Old 12-03-2014, 11:37 AM
 
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are you male or female?
is your cousin male or female?
YDNA goes from father to father to father. mtDNA goes mother to her mother etc.

So depending upon your gender you might get something out of it if your cousin is male and you are not.


My cousin tested for YDNA so that he and I could learn our male paternal line, it worked. And IMO the mtDNA did nothing to tell me anything.
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Old 12-03-2014, 11:37 AM
 
Location: Atlanta
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sorry...
both me and my cousin are MALE.
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Old 12-03-2014, 12:52 PM
 
Location: OH>IL>CO>CT
7,516 posts, read 13,621,554 times
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You may share the same 2 sets of grandparents, where "standard" first cousins only share 1, but you don't share the same paternal line Y-DNA, or the same maternal mtDna. So you don't quite have "exactly" the same ancestry (otherwise you would be brothers !)
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Old 12-03-2014, 01:21 PM
 
Location: North Carolina
10,214 posts, read 17,874,219 times
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It really depends what you're looking for. As mentioned, Y-DNA tests only provide results for your direct paternal line. Your father, your father's father, your father's father's father, etc. So if you're looking for info on your mother's paternal line, having your double first cousin Y-tested would provide that. But it won't tell you about your mother's full ancestry, only her direct paternal line.

An autosomal DNA test will provide results from all branches, but it can't specify what parts came from what ancestor. So if you want to know more about your mother's full ancestry (and only her ancestry), you would have to test her or her brother (or another sibling of hers). If they are deceased, you could test yourself and if possible, a non-double first cousin on your mom's side (so if your mom had any other siblings who had children) and you know the DNA you two share is from your mom's side and not necessarily specific to the direct paternal line.

mtDNA provides results for the direct maternal line - only your mother, your mother's mother, your mother's mother's mother, etc. Again, not her full ancestry. Even both a Y-DNA and mtDNA test together would not provide results from one's full ancestry.
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Old 12-03-2014, 02:06 PM
 
Location: Atlanta
6,793 posts, read 5,661,715 times
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Quote:
Originally Posted by reed303 View Post
You may share the same 2 sets of grandparents, where "standard" first cousins only share 1, but you don't share the same paternal line Y-DNA, or the same maternal mtDna. So you don't quite have "exactly" the same ancestry (otherwise you would be brothers !)
Right. i get that..

but I don't have any ancestors that are NOT ancestors of his as well!!... so our DNA is different bur our ancestors are the same! I was thinking i might be able to 'paint' with a broader brush because I will be able to see relatives from his Y DNA he got from his dad (my moms side) that I would not be able to see without him...
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Old 12-03-2014, 03:31 PM
 
Location: Georgia, USA
37,102 posts, read 41,261,487 times
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Quote:
Originally Posted by mco65 View Post
Right. i get that..

but I don't have any ancestors that are NOT ancestors of his as well!!... so our DNA is different but our ancestors are the same! I was thinking i might be able to 'paint' with a broader brush because I will be able to see relatives from his Y DNA he got from his dad (my moms side) that I would not be able to see without him...
Because your DNA is different each of you will be able to get matches that the other will not have. That applies not just to Y DNA but also autosomal DNA.

The more people in your family who test, the more info you will get.
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Old 12-03-2014, 09:08 PM
 
Location: North Carolina
10,214 posts, read 17,874,219 times
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Quote:
Originally Posted by mco65 View Post
Right. i get that..

but I don't have any ancestors that are NOT ancestors of his as well!!... so our DNA is different bur our ancestors are the same! I was thinking i might be able to 'paint' with a broader brush because I will be able to see relatives from his Y DNA he got from his dad (my moms side) that I would not be able to see without him...
Yes that's true but that would be true of any male child of your mother's brother. I can have my male first cousins on my mom's side (the children of my uncle) Y-tested to learn about my mom's paternal line - we don't need to be double first cousins.
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Old 12-05-2014, 09:03 AM
 
Location: Atlanta
6,793 posts, read 5,661,715 times
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Quote:
Originally Posted by PA2UK View Post
Yes that's true but that would be true of any male child of your mother's brother. I can have my male first cousins on my mom's side (the children of my uncle) Y-tested to learn about my mom's paternal line - we don't need to be double first cousins.
Good point.. I thought about that after the fact as well. THANKS!
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Old 04-25-2018, 09:57 AM
 
2 posts, read 2,021 times
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My double cousins are from 2 brothers marrying 2 sisters, seeing as how I am female and he is male will we get differant results from a DNA test?
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