Given the human propensity for both travel and having sex with the locals, anyone claiming to be a pure anything is fooling themselves. Technically speaking, we are all of mixed heritage.
True to an extent, and yet at the same time it is also true that humanity diverged into three primary genetic groups due to tens of thousands of years living in isolation and in very different environments, living very different types of lives.
The era of any sort of contact between those groups is thought to be within the last 10,000 years at most, I believe. And really, almost none in the first half of that. Most has been in the last 2,000 years out of that. For the other 8,000 it was very minimal. Even for most of that 2,000 it has been very minimal.
This was enough to create three distinct groups, even if there is still bleed over between them and even if there are subgroups of those three groups.
According to the metrics of both Ancestry.com and 23andme.com I am 100% European. Of course, biology is messy, and they are limited to looking at what we can see of genetics now, today. We cannot see all the interactions and migrations of the distant past. Though we can often discern them from molecular genetics, etc.
My results on 23andme.com list the following percentages for the groups they give you results on:
100% European
Northern European
~90% British & Irish
~5% French & German
~1% Scandinavian
0.0% Finnish
~10% Broadly Northern European
Southern European
0.0% Sardinian
0.0% Italian
0.0% Iberian
0.0% Balkan
0.5% Broadly Southern European
0.0% Eastern European
0.0% Ashkenazi
0.2.% Broadly European
0.0% Middle Eastern & North African
0.0% Middle Eastern
0.0% North African
0.0% Broadly Middle Eastern & North African
0.0% Sub-Saharan African
0.0% West African
0.0% East African
0.0% Central & South African
0.0% Broadly Sub-Saharan African
0.0% South Asian
0.0% East Asian & Native American
0.0% Japanese
0.0% Korean
0.0% Yakut
0.0% Mongolian
0.0% Chinese
0.0% Broadly East Asian
0.0% Southeast Asian
0.0% Native American
0.0% Broadly East Asian & Native American
0.0% Oceanian
0.0% Unassigned
Btw, before I'm accused of it - I am not posting this simply to be like "look how pure I am, rawr!" - I am posting it to refute the idea that nobody is entirely white or whatever. That's something you hear a lot of people saying and although as I said, biology is messy, I think within the bounds of human beings and the way we have chosen to categorize ourselves, it is completely fair to say that some people are in fact fully European or fully East Asian or fully Sub-Saharan African.
Ultimately it all comes down to what we, as humans, decide is true about these categories and classifications because they exist to express and represent things which are meaningful to us. That will always be somewhat subjective, though it can also be firmly rooted in biological reality as well, in this case.
I am also posting it because I think getting your DNA tested is a really cool, interesting use of $100 and I would recommend it to everyone. I figure if they see my results they'll have a better concept of what you get for your money, and may be motivated to do it too. I think it's neat. You get a lot more detail than what I've posted, btw.
The color scheme of the various sub-groups is based on the color scheme they use, with some concessions for legibility, and is not meant to indicate anything other than helping distinguish the broad groups and reflecting 23andme's own color choices.
I withheld my exact percentages (on the European subgroups denoted with the ~ symbol) because it's kind of personal info.
