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Paternal Lineage (Y-DNA STR) Basics This is an area for those who are new to DNA testing for genealogy can ask about Y-DNA STR based tests and their test results. All may view this forum, but you must register and sign in to post.

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  #1  
Old 6th February 2015, 12:25 PM
chills chills is offline
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Father/Son tested and match at 67 markers with GD of 2. How is this possible?

I tested to 67 markers and have my results.
My dad tested to 111 makers and he just got his results.

We match at 67-markers with a GD of 2? I wouldn't have thought there would be any Genetic distance between a father and son. Could this be a bad test?
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  #2  
Old 6th February 2015, 12:38 PM
dna dna is offline
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Quote:
Originally Posted by chills View Post
I tested to 67 markers and have my results.
My dad tested to 111 makers and he just got his results.

We match at 67-markers with a GD of 2? I wouldn't have thought there would be any Genetic distance between a father and son. Could this be a bad test?
No, there was already a poster reporting GD of 2 in a father/son pair when using 67 markers.

See the thread ydna 67 match http://forums.familytreedna.com/showthread.php?t=35648

W.

P.S.
Yes, such situations are rare, and intuitively for father/son one would only expect GD to have values of 0 or 1. However, STR mutations are independent, so larger Genetic Distances are significantly less probable to occur, but not unlikely to occur.

Last edited by dna; 6th February 2015 at 12:43 PM.
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  #3  
Old 7th February 2015, 05:36 AM
1798 1798 is offline
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Quote:
Originally Posted by chills View Post
I tested to 67 markers and have my results.
My dad tested to 111 makers and he just got his results.

We match at 67-markers with a GD of 2? I wouldn't have thought there would be any Genetic distance between a father and son. Could this be a bad test?
To ease your mind you could get a FF test for you and your father. I think that they are a great test for the money and you will learn a lot of stuff from them about yourself.
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  #4  
Old 7th February 2015, 07:21 AM
Jim Barrett Jim Barrett is offline
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Quote:
Originally Posted by chills View Post
We match at 67-markers with a GD of 2? I wouldn't have thought there would be any Genetic distance between a father and son. Could this be a bad test?
If all father/son pairs where exact matches then you would be an exact match with all of your paternal ancestors and all of their male line descendants.

Your case sounds like very good results to me.

Did you know that the president and CEO of FTDNA is not an exact match with his father at 25 markers?
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  #5  
Old 11th February 2015, 09:43 AM
sjadelson sjadelson is offline
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There has to be some possibility of a mutation, or else all males on earth would have the same YDNA. The probability is fairly small (or else YDNA would be useless for predicting close relationships), but it's there. I'm GD1/Y67 to my father.
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  #6  
Old 11th February 2015, 11:22 AM
prairielad prairielad is offline
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My father and his paternal 1st cousin are 4GD at the 37 and 67 marker level.

My Uncle and same cousin are 3GD @ 37 markers

My father and his brother are 1 GD @ 37 markers. Difference is my father registers a 2 step at DYS576 and my Uncle has only a 1 step.

I have been contemplating testing another of my uncles to see if the 4GD or the 3GD (2 step vs 1 step at DYS576)happened in my Grandfather or if my father had an additional mutation.
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  #7  
Old 11th February 2015, 04:02 PM
Wills Wills is offline
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A couple of years ago, or so, there was a post from someone who was a 10/12 match to his son. I can't remember if they ever tested more markers.
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  #8  
Old 11th February 2015, 07:10 PM
fmoakes fmoakes is offline
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My 3rd cousin and I were GD0 @ 67. When he and I tested for 111 markers we were GD1. I then tested brother, 1st and 2nd cousins for the different marker, DYS710. They are all 30 and I am 31. They just nodded and smiled.
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  #9  
Old 15th February 2015, 02:10 PM
Littlest bit Littlest bit is offline
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My grandfather has a match to a man and they share a common Y ancestor at the 4th great grandfather level. They match at 12 and 25 markers, GD1, and don't match at 37 markers even though they are both tested at least to that level. The 2 mismatches are:

DYS389-II @ 31 vs 32 and CDY @ 36-38 vs 36-39

The other man is testing to see if his terminal snp is the same as my grandfather's, should be, and it's a rare lineage (R-CTS1751). They both share the same surname, genealogy is confirmed.

Why don't they match at the 37 marker level?
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  #10  
Old 15th February 2015, 02:59 PM
Tenn4ever Tenn4ever is offline
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My husband has a 2nd cousin 1x removed and they have a GD1 and he has a 2nd cousin with a GD0 at the Y37 level.

I have two 2nd cousins with a GD1 at the Y37 level.
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