Actually, yes, and actually, no.

If you take a white person and put them in the equator for multiple generations, they'll turn brown. If you try to put the result back north, it'll take them multiple generations to get pale again.

There isn't really an inherent difference between us. There are small mutations or diseases that can kill, like Alzheimer's, but those are all basically incidental. Your genes can change, that's what evolution is.

We ALL came from Africa, anyway, and then settled down in various places for a while, adapting. The longer people have adapted, the more they've adapted. But it doesn't set anything in stone, and everybody still retains that ability to adapt.