There’s a new article in Cell about adaptation to diving in a population of ‘sea nomads’. Sledmen?
Race is real, but it’s only 70 meters deep.
You should expect significant local adaptation in any population that is effectively endogamous and has fallen into a distinct niche for a reasonably long time, say a thousand years or more.
I had vaguely wondered about these guys, but I didn’t know how long they’d been at it.