The preponderance of DNA-based genetic testing spurned this question.
Obviously the genetic makeup of the majority of European-descended people of the USA is going to be a mix of this and that, thanks to immigration, genetic mixing with the locals, and so on. I haven’t yet done the testing, but if I had to hazard a guess I’m probably 30% British Isles, 30% broadly central European, and 40% who-the-fuck-knows.
But what about in Europe? How many people in the British Isles can claim 100% descent from the early Angles, Saxons, Jutes? How many people in modern France can claim 100% descent from the Gauls or Franks? How many modern Italians are 100% Eutruscan?
No one can claim “100%” descent from any ancestor past a generation or two. LOL.
You probably only have to go back a few thousand years to get to a (modeled) most common ancestor if you define MCA as an ancestor whose gene contribution could have theoretically been distributed to anyone in the present world. (Way more complicated than that, but I’m just kind of summarizing.)
But if you are interested in relative percent of various haplotypes for a given geographic area, there are lots of sources.
I should add that the image I showed re world haplogroups is pre-1500 or so. The world (and esp w/ the European invasion of the world post-1500 and now the world invading European-centric areas) is now much more hodge-podgy because of how easy it is to jump around.
But I think ( ? ) your question has to do w/ what we typically call “source population,” right? That is, I may physically live in Billings, but if I was born to Iranian parents who themselves came from a long line of Iranians, then my “source” population is Iran’s populations; not my local Montanans (nor the original peoples here prior to them).
This article covers some of your questions in some detail:
In short, some migrations like the Anglo-Saxon invasion of Britain can be identified through the genetic analysis of human remains, and we can trace that ancestry in modern populations. However, many historical accounts of cultures, nations, tribes, etc. do not correspond to identifiable common ancestors. For example, there doesn’t seem to be a single identifiable ancestral Celtic population.
Given the location of Iran, with spice caravans coming from the east, and Macedonian soldiers of Alexander from the west, then Romans from the north, Muslim Arabs from the south, then European Crusaders from the north again, all of them raping as they travel through Iran, your Iranian ‘source population’ is going to have quite a collection of DNA.
Just like the population of the British Isles – there will be a fair amount of Scandinavian genes left there from Viking ‘visitors’ over the years.
Heck, we Homo Sapiens pretty much exterminated the Neanderthals, but recent DNA research seems to indicate that we managed to incorporate a lot of their ancestry into ourselves before that.
Seems like Chief Pedants statement is correct; humans seem a very mixed breed!
How far back do you want to go. There have been influxes from Asia to Europe going back at least 1,000 years. My Hungarian forebears are considered a distinct gene pool from the Slavs and Germans that surround them, but do you think there hasn’t been some sleeping around in the last ten centuries?
I saw a lecture by an Italian geneticist who said that as far as he knew his family had lived in the same small area of Italy as far back as they could trace for several centuries. When he did his own analysis, it turned out his mtDNA (inherited through the maternal line) was from the Middle East, and possibly Jewish. His Y-chromosome was from Central Asia, probably coming into Europe from the Huns or later invaders.
My 23andme results put me as all European (100%), with 80% British and Irish. It would be practically impossible to separate out British and Irish because there have been so many intermarriages between those countries for so long.
They then tell me that I “most likely had a great-grandparent, second great-grandparent, or third great-grandparent who was 100% French & German. This person was likely born between 1830 and 1890,” (I actually think I know who this is - a great-great-grandparent on my mother’s side. My father’s side has no records of anyone born outside the British Isles and it looks like that’s accurate) and I “most likely had a third great-grandparent, fourth great-grandparent, fifth great-grandparent, sixth great-grandparent, or seventh great (or greater) grandparent who was 100% Scandinavian. This person was likely born between 1710 and 1830.” I haven’t found all the records for eveyone born during that long time and of course it’s likely there are a few records that are not of the real father (and possibly mother). So they had to go back to 1860 or so to find someone who wasn’t British.
However, they assume this figure based on DNA records they have access to, which includes their own customers plus “publicly available data from the Human Genome Diversity Project , HapMap , and the 1000 Genomes project.” Those people are probably self-reporting their ethnicity, which means there could be some inaccuracies. For Europe the numbers are probably large enough that this doesn’t matter, but they have a whole 39 people from Oceania to test against, so the accuracy there is likely low. Obviously as more and more people sign up and consent to research the results will get more accurate - the figures in my report have actually changed since I first got them.
I don’t find it that unlikely that some people are actually 100% British Isles, or will turn out to be once they have enough data to support that. Even now people tend to marry people from their local area and in the past that happened far more. There was that excavation in Cornwall where they dug up a prehistoric man and discovered he still had an ancestor among the small population they tested at the local school (I can’t find a link, sorry). Cornwall may be a special case - for a long time the main contact Cornwall had with the outside world was via sea trading (mostly tin) and that makes incomers contributing their genes not very likely - but my paternal ancestors are all from London and nearby and still seemed to only marry their immediate neighbours.
British and Irish doesn’t just mean Anglo-Saxon and Jute though, even if you exclude the Irish section - there were people here before the middle ages and they didn’t all suddenly stop breeding once the invaders arrived. So no, I’d be astounded if there was ever anyone Anglo-Saxon and Jute only because they don’t even test for that.
Bear in mind that the geography of the UK is such that there are two coastal trade routes to Europe. Scotland, Ireland, Cornwall, Britanny, then along the coast of France to Spain and Mediterreanean. The other faces Norway, Scandanvia and the Baltic then Low Countries and France. These differences are preserved in the language and dialect.
The Roman Empire had a road network across Europe and they had a policy of relocating their recruits far from their home. The British end of the Roman empire would have had a fair range of genes from distant parts of Europe. When the British Empire got going in the 17th century, it opened the UK to world trade by ocean going ships and this would have have opened up the UK to lots of visitors from distant lands. One feature of Empires is they allow people to move around. Anyone who lives near a port would have been quite accustomed to meeting foreigners. Some, no doubt, exchanged more than commercial goods. The British are a very mixed people, there has been a lot of outbreeding.
Eddie Izzard pursues this theme in Mongrel Nation:
I am not sure there is a great deal of virtue in living for many generations in the same area. Inbreeding increases the risk of genetic disease. The Icelanders have this problem and they have to be careful about who they date. Though this also makes it a useful for identifying associations between genes and health;
This sounds a lot more useful that identifying ancestry. Besides a few interesting family histories, what does it matter where the genes came from? You don’t have to go too far back? What interesting secrets might be revealed if everyone compared their own genome with that of other members of their family?
For similar reason, phrases such as “a real Spaniard”, “a pure Spaniard” or “Spaniards first” are a huge joke; we say that “every Spaniard has in his family a king, a whore and a jew”, and also that “all those invaders coming by may have stayed put or not, but they all found time for the whores”. The few xenofascists who use those first phrases in actual seriousness will, when pressed for a definition, blurt out “I know it when I see it!”. Our local nationalisms have a good bit of xenophobia and it just makes my head hurt to hear people say something like “people should just stay wherever they were born!” when their own parents or grandparents were born in different regions or nation-states.
My Dad’s first 32 lastnames were Basque… from all seven provinces (four in Spain and three in France) and the 2nd one was from Rioja before moving to Vizcaya. My maternal line is from a tiny village in Asturias, but my mDNA says “eastern Mediterranean”: ok, great-grandma, who went fooling around with whom on some summer night :dubious:? Other ancestries of mine include northern Italy (possible fake lastname, to make it more fun), Naples and the NE of France.
Remember: there is no such thing as a genetic marker for nationality. DNA testing at best can say “some of your genetics match traits that we’ve arbitrarily assigned to this nationality at the moment.”
You get different results from different testing organizations, and even different results from getting tested by the same organization twice. The person interpreting the results can choose several nationalities from the same result. There was an article recently (possibly on Cracked) that outlined just how they make their choices
Ultimately, the question can’t really be answered, since you’re measuring things with broken yardsticks.
We don’t have a good database of genomes from Angles, Saxons and Jutes from the 5th century, and even if we did, it would be unlikely that either of those three populations were, themselves, “pure”.
I think Morgenstern is indicating the probability of breeding with people who don’t live on Sentinel Island by the Sentinelese is most likely near enough to zero to not matter.
What is the source of your information that nobody can be sure of who his ancestors were beyond the first two generations due to infidelity and not simply bad records? If you’re assuming such high levels of infidelity, why would the last two generations be believable and the previous ones not?
