From time to time I am struck by the fact that, as a species, human beings can be so remarkably homogeneous. All the more remarkably as there is this common-sense intuition that we can even be divided into groups. Before, they called those groups races, but they changed that into ethnic groups as this use of the word race would be blatantly at odds with its use elsewhere, like, when it is used to refer to varieties of mostly inter-breedable animals that nonetheless differ by being the one 10 times heavier than the other, or the one not having fur at all while the other has a thick coat of it. Even with the name change, I would dismiss the biological substratum of that idea as a political strategy in the guise of a scientific statement.

When one start to think of the less external features of human beings, like the capabilities of processing well this or that nutrient or seeing that color or not, human beings are extremely similar, the variation being mostly restricted to minor personal variation carried on in the genes and generally not surfacing on all generations (I am thinking of stuff like colorblindness or the people living in that little city in the middle of nowhere in Europe whose organisms process fats better, and so are only minimally prone to heart diseases).