Here’s another not-yet-peer reviewed brand new DNA study: this one looks at 6,267 New World individuals who are at least 10% sub-Saharan by ancestry to see where their black ancestors were from in Africa. This helps explain the pattern seen in Olympic running were English-speaking blacks tend to be better at the 100 meter dash than Brazilian blacks.

Origins, admixture dynamics and homogenization of the African gene pool in the Americas
Mateus H. Gouveia, et al

This article is a preprint and has not been peer-reviewed

The English colonies were supplied more by black slaves from the West Coast of Africa (the Sprint Coast), while Brazil drew somewhat more from South and East Africa (the Distance Coast), such as the Portuguese colony in Mozambique.

Indeed, West Central Africa- and West Africa-associated ancestry clusters are more commonly observed in northern latitudes, while the South/East Africa-associated ancestry cluster is more evident in southern latitudes.

Indeed, in the 1990s a black Brazilian set a new fastest time in the marathon, which would be extremely unlikely for a typical U.S. black.

Granted, this was already known from the historical record, but it’s interesting to see it confirmed in the DNA.

But there aren’t huge differences between the various black populations in the New World:

The African gene pool is more homogenous between-populations in the Americas than in Africa.

Once again, this was already known from history: the slave trade mixed a lot of different types of blacks together. Also, due to the vast prehistoric Bantu expansion, most of the coastal blacks of Africa are relatively similar in the first place.