What do you mean "it replicates worldwide"? What replication are you referring to?
I'm really asking, by the way! If you meant to say "group differences in intelligence have replicated in other countries, like in Europe", that's noncontroversial. But if you mean to suggest that we have actual global data about IQ --- forget inter-group intra-country, just data for most of the world at all --- I think the story there is we do not.
IQ differences between ethnic/population groups/racial groups. It's not only a US phenomenon
I don't think it's a US phenomenon in particular; I'm saying we have data about the US, and not about the rest of the world.
Then you haven't looked
People tend to say this before citing "IQ and the Wealth of Nations" or something derived from it.
The US racial groups are US specific. The bundling of different ethnicities into a race (like grouping high pigmented out of Africa with Africans instead of with low pigmented out of Africa) is silly.