Diagram giving an overview of the admixture process. When two populations admix, genetic recombination starts breaking ancestral genomes into blocks of different sizes, so that the genomes of the descendants of an admixture event are composed of different combinations of these ancestral blocks. The number and width of the admixture blocks contain information about the time since admixture, as more recombination events result in a greater number of blocks, which with time get progressively narrower and more evenly spread along and among chromosomes.
Pugach et al. Genome Biology 2011 12:R19 doi:10.1186/gb-2011-12-2-r19