Indeed. I heard one of the PIs on the 100,000 genomes project [1] giving a talk in which they flat-out said that anyone whose four grandparents were white and irish is basically a clone compared to anyone whose four grandparents were from sub-saharan africa. The whole point is that there's so much variability within each societal clustering that it tends to make not that much sense to talk about it -- and the degree of homogeneity is different, too, mostly depending on ancient geography (hello Iceland, as an example).

There are lots of "exceptions" to this, like sickle cell anaemia, for example [2], which is used as a teaching example of an Mendelian autosomal recessive disease. But note that it goes hand-in-hand with a historical pattern of malaria, covering a fairly large and inhomogeneous blob of africa, the middle east, italy/turkey/greece and india. Our social construct of race varies quite substantially over those places.

[1] https://www.genomicsengland.co.uk/about-genomics-england/the...

[2] https://en.wikipedia.org/wiki/Sickle_cell_disease