Emil O W Kirkegaard

And it’s also possible for a trait to be “racial” while being more strongly influenced by environment than by genetics (as long as it has a genetic component).

Well yes I guess every genetic trait is more common in some groups than others. The question is how much that matters. When it comes to myopia the answer seems to be not much.

Let's look at an example in birds. The Carrion (Black) Crow and the Hooded (Grey) Crow are extremely close genetically and capable of producing viable offspring. They have a relatively wide "hybridization zone" in Germanyhttps://twitter.com/Locus_of_Ctrl/status/1005531827140874240 …

Furthermore, according to some PCA analyses, the Carrion Crows in Spain are more distinct genetically from the Carrion Crows in Germany than the latter are distinct from Hooded Crows in Poland. (aka more genetic variation inside the group than outside)

Nevertheless, the visual distinction between the two "races" of crow does impede hybridization to some extent (the fully black birds seem to be more attracted to fully black mates and vice versa).

For this reason, if you moved the "more distinct" Spanish Crows to Germany, they would probably mate with the German Carrion Crows rather than with the German Hooded Crows.

For this reason again, it is not entirely stupid to group visually distinct birds into visually-derived categories even if the underlying genetics show a more complicated picture. The comparison to humans is obvious.

NB: Because of crows' ability of flight, the absolute genetic distinction between Carrion and Hooded Crows is probably significantly smaller than the distinction between humans with ancestral origins on different continents.