Buffalo mass shooting - Great Replacement Theory & the long trail of blood

Slaves. Not exactly a great point for migration.

Roman culture was a mix, but it was far less a mix of people. And of course they were an imperial power, so what people did migrate into the greater Roman world, or were subjugated by it, to have any chance of an easy life and certainly a prosperous one aping Roman customs and culture was a given. So adopting the dress, religion, language, building styles, naming your kids with Roman names etc. Or they were a slave. They were at times very proud of the "world" being represented in Rome, where you could see and hear "foreigners" about the place. At the same time it was considered good business and on the statutes of slave trading to declare where your slave was from, as different origins got different prices. Those from "evil nations" were cheaper.

And given your examples of the goths etc migration it seems the locals had very good reason to be fearful of the other as when they crossed the Rhine that was the death knell of their culture and empire. Even simple things like pottery stopped being produced, with literacy and writing fell off a cliff for a couple of centuries. Again not a great point for migration. There's a reason we still call those who destroy things with no obvious purpose "vandals".

So to recap: Your examples of stable and successful societies of the past with "diversity" were either diverse because of slavery, or empire building subjugating the other and in each case the dominant culture was, well, dominant and only multicultural if and when it suited the dominant culture and when it started to lose that dominance the culture was on the way out.

Yeah. African populations have the widest genetic diversity as Africa is where anatomically modern humans evolved and then later on got the wanderlust(like Homo Erectus way before that. Those buggers were like New Zealander college students😁) and spread into the rest of the world. A Norwegian and a Greek are more related to each other than say a Gongalese and a Tanzanian living twenty miles from each other could be. When some of us left Africa it got interesting as we were going into places where there were already people and got jiggy with them. Europeans and Asians have archaic hominid genes and active ones too, so clearly had/have some purpose if they've survived even down to today. An obvious one is Nepalese and Tibetan folks who got genes from Denisovans that give them a big advantage in living at altitude. Africans have their own archaic admixture but recovering readable DNA in those climates is difficult, but there are clues in living people.

The interesting thing about pale skin is native Tasmanians who lived in a climate very like Europe only on the other side of the world were and remained a very dark people over tens of thousands of years. Farming may have been the driver in the northern hemisphere. That because Tasmanians never developed agriculture their hunter gatherer diet being more varied and nutricious than a farmers diet meant they got folic acid and vit D from their food, so didn't need to evolve pale skin(though Neandertals who had a similar lifestyle had pale skin, with a couple of gingers thrown in. Different genes to us though). Asians can be very pale, but their pale adaptation uses different genes to Europeans. Better genes too. EG they have about the same rates of skin cancer as Africans and are less prone to sun based skin damage than pale Europeans.

But I digress. 😁