Genealogy & Family History Stack Exchange is a question and answer site for expert genealogists and people interested in genealogy or family history. It only takes a minute to sign up.
Sign up to join this community
I did an ancestry DNA test to find out my ethnicity. Obviously I'm African-American, but the test revealed to me that there were five different ethnic groups running through my blood and they were African (Cameroon) Asia (Afghanistan) Europe (Germany, Great Britain, Ireland) West Asia (Polynesia) & Pacific Islander.
Why are there so many different ethnicities in my DNA?
Both of my Parents are full blood African-Americans and so are all of my grandparents.
Unfortunately, all ethnicity calculators are not precise. So they can give absolutely different and unreliable results. For example, MyHeritage's ethnicity calculator gives for my mother British ancestry. It is completely wrong. She is Hungarian, so Balcanian and Central-european ancestry in results is OK. I can guess that such a result may be result of small amount of Hungarian ancestry in reference British results, but we can't prove it, because all algorithms and reference data are private.
If you would like, you can try to use GEDMATCH site. It is completely free. You download there your autosomal data and different analysis tools become available. Among them there is a lot of competitive calculators. And you may crosscheck your results with them.
Also the calculators work relatively well when your parents and/or grandparents from monopopulation. If they are also mix of different ethnicities, the calculators will probably fail and don't show the original ethnicity (for example, West-European + South-African) but some average population (like Mediterran, what is erroneous)
The short and simple answer is that when AncestryDNA gives you an estimate of your ethnicity, they're just guessing. Each company has different ways of making the estimate, and over time, they try to refine the estimate -- but it's still an educated guess.
In her Apr 16, 2017 post "Still not soup" on The Legal Genealogist, Judy G. Russell explains:
[A]dmixture tests ... take the DNA of living people — us, the test takers — and they compare it to the DNA of other living people — people whose parents and grandparents and, sometimes, even great grandparents all come from one geographic area. Then they try to extrapolate backwards into time.
and she goes on to say:
In other words, these percentages are:
• estimates,
• estimates based on comparisons not to actual historical populations but rather to small groups of people living today, and
• estimates based purely on the statistical odds that those small groups tell us something meaningful about past populations.
The companies do refine their methods of making estimates, and sometimes publish detailed explanations about how they arrived at the estimates. Ancestry has published a whitepaper on their Genetic Communities™, and they've made their 2013 Ethnicity Estimate White Paper available, so if you want to plunge into population genetics and read all about it, you can.
But as Russell points out, the fundamental difficulty is the assumption that looking at a population that has been in the same place for a limited number of generations can predict what that population was thousands of years ago. Your DNA is not being compared to old bones which have been dug up -- it is being compared with a (possibly) moving target.
For more on AncestryDNA's ethnicity estimates, see the article about AncestryDNA at the ISOGG Wiki. (Thanks to Debbie Kennett for the link to the Genetic Communities white paper.)
There's no such thing as a "full-blooded African American". By definition, African American people have a mixed ethnic background with roots in African countries. Depending on how dark you are, you may have more or less African blood, but you will also certainly have European ancestry to as your ancestors who came to America as slaves would often have children with their masters or later in history have children with men of European descent of their own free will.
Who's to say for sure where the Afghanistan blood or West Asian comes from? Ancestry DNA tests can sometimes get things wrong, so you never know unless you trace your family tree as best you can.
Everyone has mixed DNA to an extent unless their ancestors and themselves have lived in isolated rural communities for millenia (ie indigenous people).
As an example, my father is Maltese by birth and my mother is British. If I did an ancestry DNA test I would have British blood, North African (from the proximity to Southern Italy) probably some middle eastern and certainly some French or German from all the invasions that have come to England over the centuries.
