[dogscoff]

Realistically, when individuals emigrate to other places they tend to do it with people they are familiar with, who tend to be from their same culture, so you will probably expect to find many ethnically restricted planets.

Personally, i think it is more likely that ethnicity will eventually cease to exist if globalisation continues at its current rate. Space colonisation would probably accelerate the process.

As more and more babies are born with parents of different races, completely white/ completely black/ completely {insert ethnic grouping here} people will become more and more of a minority compared to the growing group of mixed heritage somewhere-in-the-middles. Eventually, dozens or hundreds of generations into the future, everyone will be the same colour.

Looking at the proportions of ethnic groupings in the current world population (ie the vast majority of the human race being in China and the 3rd World), you can try to guess at what the final colour of humanity might be. All those white supremacist arseholes are in for a shock

Granted, loads of people, for whatever reason, find people of their own colour more attractive or at least more available, but eventually globalisation will change this.

This might one day spell and end to racism, which can only be a good thing, but the loss of diversity saddens me. Then again, by that time we'll have the tech to modify our bodies' colour as easily as changing our clothes. Being black or white might one day be nothing more than a fashion statement=-)

It also makes you wonder whether 200 generations ago there might have been racial Groups and genetic features which have been bred out altogether now...