African American DNA Research Forum
DNA Tribes Explanation
Here's their response for trying to calculate percentages. They say you can't really do it. So my friend was off a bit. There are some similarities, but I can't trust his numbers. I want to see what you're able to come up with Chris.)I'll just have to get the Ancestry by DNA test afterall! Here's DNA Tribes response:
Our method of identifying and measuring genetic connections to populations and major regions is not based on a percentage approach. For this reason, the numbers included in our reports cannot be used to calculate a percentage. Instead, we measure relative connections with various regions. We have chosen this approach because in general, all living people share ancestry with each other to some degree.
To perform a percentage estimate, it's necessary to know exactly what a person's source populations were and when they came in contact and admixed. This approach can be useful when these factors are known: for instance, a person's estimated percentage of ancestry from known source groups can be helpful for measuring disease risk. However, this kind of estimate doesn't apply for general purposes when these factors aren't known or don't apply. This is why our analysis emphasizes genetic connections, and identifying which are strongest and measuring their relative strengths.
At one extreme of scores, some sample profiles can obtain very high scores when they are very typical of one region/group and not others. At the other extreme, a person whose ancestry was evenly distributed amongst all major regions would obtain a score of "1" for all regions. However, most individuals have substantial genetic connections to particular region or regions of regions of varying strengths.
For your profile, we do see Continent Match scores above 1 for South Asian, Asia Minor, and European in addition to a stronger score of 56.7 for the Sub-Saharan African region. These smaller scores reflect secondary ancestry in your background. What usually happens is that genetic signals become weaker with each generation, and at some point cross below the Generic Human Threshold of "1," meaning they can't be distinguished from the ancestry we all share. We don't see Native American for this profile, but someone further up your family tree might retain these Native American genetic signals strongly enough to show up.
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