One of the more remarkable results in 21st human genetics was that the top two PCs of a genotype matrix captures geography to an amazing degree [1]. This is the

One of the more remarkable results in 21st human genetics was that the top two PCs of a genotype matrix captures geography to an amazing degree [1]. This is the PCA of a N x M matrix where you measure M genetic markers in N people in a relatively homogenous population (Europeans in the paper above). 1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2735096/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2735096/