 PC1 separated Africans from the other populations, PC2 divided Asians from Europeans and Africans, whilst PC3 split Central Asians apart from South Asians.According to Cavalli-Sforza's work, all non-African populations are more closely related to each other than to Africans, supporting the hypothesis that all non-Africans descend from a single old-African population.The genetic distance from Africa to Europe (16.6) was found to be shorter than the genetic distance from Africa to East Asia (20.6), and much shorter than that from Africa to Australia (24.7).