Here of all places this is unnecessary. I posted the link specifically hoping someone would respond like this.
Mission accomplished! :-)
If we’re discovering clusters that don’t fit with our racial preconceptions that is evidence the clusters that do match some of our racial preconceptions aren’t bullshit.
Sounds reasonable.
Also, aren’t we looking for genetic evidence of cultural and geographical isolation? Isn’t the fact that we see different clusters for different groups in Africa just evidence that those groups have been (reproductively) isolated for a really long time?
It can be, although variation along principal component axes can also represent genetic change due to migration. (I picked up on this potential confound by reading a Nature Genetics paper that made the same point from the opposite direction. That is, variation along a PC can be due to continuous geographic separation instead of migration.)
Also, from the chart posted here I would predict that the Africans kidnapped and purchased as slaves came more from the Yoruba and much less so from the Mandenka.
That’s looks about right to me. Table 1 from the paper estimating African ancestry gives a detailed breakdown of the African ancestry of the African-American sample, and it fits what you suggest.
Mission accomplished! :-)
Sounds reasonable.
It can be, although variation along principal component axes can also represent genetic change due to migration. (I picked up on this potential confound by reading a Nature Genetics paper that made the same point from the opposite direction. That is, variation along a PC can be due to continuous geographic separation instead of migration.)
That’s looks about right to me. Table 1 from the paper estimating African ancestry gives a detailed breakdown of the African ancestry of the African-American sample, and it fits what you suggest.