Admixture analysis assumes a fixed number of ancestral populations and estimates a percent ancestry of each ancestral population for each sample. The resulting quantitative values are substantially more informative than SIA, can be used to assess sample homogeneity, and divide the sample into sub-populations if there are large differences. There is a variety of software designed to perform these analyses including ADMIXTURE,5 FRAPPE,7 sNMF.8 However, creating more homogenous subgroups using admixture results can be challenging if there are no clear clusterings of individuals. Subdividing by global ancestry may not be sufficient to address population stratification when local population structures exist.
