This story is a supplement to the feature "The Migration History of Humans: DNA Study Traces Human Origins Across the Continents" which was printed in the July 2008 issue of Scientific American.
Looking Far and Wide
High-powered genetic sequencing and computational techniques developed for the Human Genome Project and in its aftermath have furnished a wealth of data that lets researchers compare genomes drawn from distinct populations around the globe.
A genomic map of the world (below), crafted by researchers at the University of Michigan at Ann Arbor, shows that genetic diversity decreases outside of Africa. Each colored tile represents a common haplotype. Africa has more tiles than found on other continents and ones that correspond to haplotypes found nowhere else.