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  #1  
Old 13th March 2018, 04:27 PM
Daley Daley is offline
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Meaning of Genetic Distance

So i recently got a test kit done and I have some basic questions that I I hope someone can answer for me or direct me to a place where I can find the answer

The section that lists the genetic distance -1 and -2. What does that mean?

And the exact match section? what does that mean?

Im so confused, lol

thanks
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Old 13th March 2018, 05:00 PM
John McCoy John McCoy is offline
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The answer depends on what test you took.

For Y-DNA tests, "genetic distance" simply means the number of differences between two samples. If two samples, both tested for the STR markers in the Y-37 test, match exactly, they have a "genetic distance" of 0. If they differ at two markers (simplifying here, there are a couple different ways to compute this), that's a "genetic distance" of 2. The greater the "genetic distance", regardless of how it was computed, the less likely it is that the two samples are closely related in terms of genealogy. But exactly how close the relationship is likely to be, depends on the mutation rates of the individual STR markers as well as how many STR's were tested, so it is not a good idea to compare "genetic distances" for pairs of samples that came from different tests. That is, a "genetic distance" of 2 for a pair of samples from the Y-37 test doesn't mean the same thing, necessarily, as a "genetic distance" of 2 for a pair of samples from the Y-67 test.

Some people also use "genetic distance" (loosely, and I think, erroneously) to talk about how close two samples are when tested with the Family Finder test. Best not to go there -- it is probably much clearer to refer to the "estimated generations" back to the most recent common ancestor, rather than calling that number a "genetic distance".
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Old 13th March 2018, 05:52 PM
prairielad prairielad is offline
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In regards to yDNA, a rough outline of Genetic Distance for each level of STR testing can be found in following link.

These charts are base on the average rate of STR marker mutations. One can be higher then average or lower then average which will skew results....

12marker
https://www.familytreedna.com/learn/...s-interpreted/

25 marker
https://www.familytreedna.com/learn/...s-interpreted/

37 marker
https://www.familytreedna.com/learn/...s-interpreted/

67 marker
https://www.familytreedna.com/learn/...s-interpreted/

111 marker
https://www.familytreedna.com/learn/...s-interpreted/
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Old 13th March 2018, 06:19 PM
Daley Daley is offline
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Thanks for the replies


So when I see that the portion of the report that lists countries and has a genetic distance number on there with a percentage - Does that compare my sample to the average person from that country?
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Old 13th March 2018, 07:16 PM
John McCoy John McCoy is offline
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Alas, I don't think there IS a reliable figure for "an average person from that country".
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Old 13th March 2018, 09:47 PM
prairielad prairielad is offline
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Quote:
Originally Posted by Daley View Post
Thanks for the replies


So when I see that the portion of the report that lists countries and has a genetic distance number on there with a percentage - Does that compare my sample to the average person from that country?
Ancestral origins lists your matches self reported country of origins and gives you a percentage of your matches which self report that country of origin against all in database which list that country as country of origin.
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File Type: png ancestral.png (22.5 KB, 11 views)
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Old 14th March 2018, 11:58 PM
Daley Daley is offline
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Prarielad,

Thanks for the reply !
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