(Updated May 1) The importance of this new paper from the
Tishkoff Lab cannot be emphasized enough. It is probably the
most comprehensive study of African genetic variation to date.
The supplementary material (pdf) is itself 102 pages long and
should keep you busy reading for a while (free for non-
subscribers). What this study has found in a nutshell is that
"black" Africans belong to 14 distinct clusters. Black Americans
belong overwhelmingly to the Niger-Kordofanian cluster,
consistent with their origin largely from Western Africa. The
paper covers the levels of diversity in different African
populations, finding that: Within Africa, genetic diversity
estimated from expected heterozygosity significantly correlates
with estimates from microsatellite variance (fig. S4) (4) and
varies by linguistic, geographic, and subsistence
classifications (fig. S5). Three hunter-gatherer populations
(Baka and Bakola Pygmies and San) were among the five
populations with the highest levels of genetic diversity based
on varia