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Old 09-20-2013, 11:46 PM
 
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On a well known genetics site, I share the same exact Y DNA haplogroup with someone who has the same exact last name as mines. However, I'm black, and he's white. My paternal lineage comes from a former British colony, and he can't trace his ancestry beyond America. Could it be a mere coincidence, or it's possible we have a common ancestor going back generations to Britain/Ireland?
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Old 09-21-2013, 04:16 AM
bjh
 
Location: Memphis - home of the king
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It could be a shared ancestor or it could be coincidence, especially if it 's a fairly common last name.
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Old 09-21-2013, 06:16 AM
 
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Quote:
Originally Posted by bjh View Post
It could be a shared ancestor or it could be coincidence, especially if it 's a fairly common last name.

It's not common.
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Old 09-21-2013, 08:19 AM
 
Location: Georgia, USA
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Quote:
Originally Posted by knowledgeiskey View Post
On a well known genetics site, I share the same exact Y DNA haplogroup with someone who has the same exact last name as mines. However, I'm black, and he's white. My paternal lineage comes from a former British colony, and he can't trace his ancestry beyond America. Could it be a mere coincidence, or it's possible we have a common ancestor going back generations to Britain/Ireland?

Since you are both male, you can compare Y-DNA. Which site did you use?
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Old 09-21-2013, 11:01 AM
 
Location: Illinois
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If you are especially interested you both should invest in STR testing.

Y-STR - Wikipedia, the free encyclopedia

In the meantime why don't you guys concentrate on comparing family locations and using census records to see if you share a common ancestor?

Also, does he have an NPE (Non Parental Event aka missing ancestor) that is preventing him from tracing past America?
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Old 09-21-2013, 02:29 PM
 
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just because you share the same haplogroup doesn't mean you are related, now if all your marker in that haplogroup was the same, then its a possibility, 12 marker, 37 markers, not going do it, but if you share 111 marker. also it won't tell you if you are related, it will only tell you if you are not. that hard to understand, if your marker do not match, you are not related. but the y tree can go back thousands of years
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Old 09-21-2013, 02:45 PM
 
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On 23andMe they have a feature where you can so a simple match up to another person in the database and see similarities in DNA. Through this feature, I was able to see that 29% of my DNA came from my maternal grandmother (she also took the test). If that is the test you took then you may be able to match up to them and see how genetically similar you are to them. If the similarity is larger than 5% then you are probably not that far removed from each other.
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Old 09-21-2013, 04:40 PM
 
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Quote:
Originally Posted by suzy_q2010 View Post
Since you are both male, you can compare Y-DNA. Which site did you use?
23andme
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Old 09-21-2013, 09:59 PM
 
Location: Georgia, USA
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23AndMe uses a different technology and does not give you the Y-STR CMichele mentioned above.

However, I am assuming that you and the other person with your name do share some DNA. How close is the relationship? A larger percentage of shared DNA and more than one segment suggest a closer kinship. You could ask him if he has already had Y-DNA testing. If he has, you could use the same company and get yours done. If not, you could agree on one to use. My brother and a male cousin have tested through Family Tree DNA.

Family Tree DNA - Genetic Genealogy Starts Here

Don't bother with the 12 marker test because you will get too many matches and figuring out the relationship will be hard. Do the 37 marker. If you are related through your fathers' lines, that should confirm it.

The other person could benefit more from the information than you will, since you can apparently trace who the immigrant to the American continent was and and he cannot.

Even if the two of you turn out not to be related through your fathers, doing the Y-DNA test could help you find someone who does match.

Of course, doing more tests can get pricy.
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Old 09-21-2013, 10:25 PM
 
Location: Georgia, USA
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Quote:
Originally Posted by brownbagg View Post
just because you share the same haplogroup doesn't mean you are related, now if all your marker in that haplogroup was the same, then its a possibility, 12 marker, 37 markers, not going do it, but if you share 111 marker. also it won't tell you if you are related, it will only tell you if you are not. that hard to understand, if your marker do not match, you are not related. but the y tree can go back thousands of years

Twelve markers does give you more matches that are not useful, but 37 markers should be plenty. Not many folks want to spend the money to test 111 markers.

You still have to do the search of the paper record to try to find out who the potential common ancestor is. If you match, you are related, but the test cannot tell you who the common ancestor was or when he lived. When you find a match, you have to compare family trees, looking at where ancestors in your father's male line lived and try to find both families in the same place at the same time.

I cannot find out who my father's third great grandfather was. However, my brother's Y-DNA matches three other men who have traced their lines back to VA. We have them all in the same general geographical area, but right now we still cannot tie those four families together. It is helpful to find that you do not match a specific line, too. That tells where you do not need to look. If you do not match 12 out of 12, you are not related.

See here for an explanation of the probabilities involved:

Probabilities in DNA

"37/37 match means, with 90% confidence, that your MRCA [most recent common ancestor] probably lived 150 years or less before you were born."

The article also explains that if you are certain who your most recent ancestors are and you do not match in those generations, it shifts the odds that the match is in the generations just preceding the ones you do know.
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