I appreciate that on these racial topics we're getting into religious territory for you, and I also appreciate that we're getting very off-topic. However, I feel I should make at least some effort...
Soap wrote:
If a thousand Nigerians and a thousand Swedes had gotten together long ago and settled the Americas from the east, after 12000 years of habitation they would have developed into a perfectly homogeneous population. I'll call them Afropeans. If we tested the Afropeans genetically in 10000 BC, we'd find that they'd be intermediate between the Africans and the Europeans of their time. We'd get the same result if we tested them a few thousand years later ... they'd have mixed, but their overall genetic profile would be exactly the same as it had been before .
If a thousand Nigerians and a thousand Swedes had populated a continent together, what you'd see would be considerable genetic variety. Those 2000 people would have had many, many different genetic mutations, which would be passed down and combined in many different ways. Some of the variety would indeed by flattened out by the scale of the population explosion, but a lot of it would remain.
What we in fact see in the Americas is the opposite. Not only does the population derive from a small number of founders, but those founders must have been closely related to one another, and isolated from everybody else.
For example, over 80% of indigenous people in almost all parts of the Americas (with the notable exception of Na-Dene) are descended from
one specific man, who lived probably less than 20,000 years ago.
Over 90% of the entire indigenous population of central and south america is in particular descended from
one specific man who lived less than 15,000 years ago.
And it's not just the y-dna that's like that - it's the whole of the DNA. [in contrast to parts of europe, say, where a lot of male descent is from a small number of Indo-European invaders, but female descent is much more varied, indicating intermarriage with an existing population].
Specifically, combining modern and prehistoric samples, we can say: (virtually) the entire population of central and south america forms one group, and most of north america forms a second group, and the two groups split off surprisingly quickly from a parent population in the far northwest, which given the time period and the climate we can deduce must have been living in the Beringian Refuge, where both genes and palaeoclimatology indicate they had been isolated for thousands of years.
That's not what you get if you randomly mix together nigerians and swedes.
Now assume that, in later times, Europe and Africa were settled by other incoming waves of people from various places ... let's just say Asia. These people, however, did not move on to also settle America. Therefore, after a few thousand more years, the Afropeans living in America no longer show a close genetic match to either the Africans or the Europeans, since they entirely lack the genes of those newcomers. Therefore they are a racial isolate, appearing to be an independent branch of the tree, one that separated from the European and African branches
Americans did not come from Africa or Europe, they came from northeast asia, and their closest relatives are mostly still in northeast asia.
There's no such thing as "racial isolates" or "independent branches"; everyone's genetic history remains within them. For instance, just looking at Y-DNA for the sake of simplicity: the American population is almost all from Haplotype Q, and specifically just a few branches of Haplotype Q. So their closest relatives in the male line are people from other branches of Q. And the closest relatives of people with Q are people with P and R (Q and R are both subtypes of P). And so on. And when you look at the entire autosomal DNA, you can also find out about substrate populations. And it can get very complicated due to multiple movements of peoples at different times and back-migrations, and the lack of sufficient ancient remains to work out exactly where everyone was at particular times, particularly in crossroad areas.
But in the case of the Americas, we don't need any of that, because it's such an open-and-shut case. There is no evidence of any substrate population. There is no evidence of complex population structure in the founding population. There is no evidence of any later migration to the Americas outside the Arctic, other than the Na-Dene, until the arrival of Europeans. Other than 'tiny overlooked tribe', the only way to get non-Amerind languages is to assume that some Na-Dene got lost, intermarried heavily with the locals (even more heavily than the rest, I mean), and had their language get so weird it hasn't yet been identified as Na-Dene. And then we have to acknowledge the theoretical possibility that this happened not with the Na-Dene but with a companion group, genetically closely related but linguistically distinct. So strictly speaking it's possible there might be a rogue family somewhere in north america, but it's pushing the bounds of plausability.
Otherwise, we can say with extreme (if not perfect) confidence:
- American languages are divisible into the Na-Dene, Eskimo-Aleut and Amerind families
- Amerind is divided into two main subfamilies: Northern and Southern.
- Southern contains all the languages of south america, plus most of the languages of central america
- Northern probabbly contains all the languages of north america and maybe a few of central america
- It's possible that there might be a few Amerind families in north america that don't fall within Northern, though not likely; if they do exist, they're probably somewhere on the west coast.
... not just before the Asian migrations, but before the Asians even existed.
Just to point out: East Asians and Europeans are actually relatively closely related.
Yet we know from above that their original founding population was highly heterogeneous, and that they were not speaking the same language when they arrived on the shores of America.
Even in your scenario, if you take 1000 Swedes and 1000 Nigerians and keep them at approximately that population size in a handful of neighbouring villages with no-one else to marry for thousands of years before letting them colonise the Americas: it's really, really likely thatthose 2,000 people will have ended up speaking the same language by that point.