It is happening again in Britain and it won’t take 300 years to replace the population.
But the story changes when the Bell Beaker culture expanded to Britain after 4,500 years ago. Then, it was brought by migrants who almost completely supplanted the island's existing inhabitants - the mysterious people who had built Stonehenge - within a few hundred years. "There was a sudden change in the population of Britain," says Reich. "It was an almost complete replacement."
Immigrants replacing the natives...now where have I heard that before. Somewhere, somewhere recently....
It happened even faster to the Indians of North America.