Between 1848 and 1850, four thousand one hundred and fourteen girls were taken out of Irish workhouses and put on ships to Australia. Most of them were between fourteen and twenty. Most had no parents living. Because there genetics was Northern Europe this was a kind of immigration that worked seamlessly. It worked in spite of the fact that they were from the lowest socio economic background in Europe. No one was dumb enough to bring in 4k Africans but if they did it wouldn't have worked because of the genetics. They would still be an underclass today in stead of completely integrated. We know this because this is what happened everywhere it was tried.