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For perhaps the first 100,000 years or more, genetic variation was developing as human populations largely migrated within Africa between 300,000-200,000 years ago. Anatomically modern humans derived from these <i>Homo sapiens</i> species, although by then other similar species, such as Neanderthals, had existed. Genetically, Y-chromosomal Adam, or the genetic ancestor for all living men today (i.e., although this does not mean he was genetic Adam was the only man around), seems to derive between 300,000-200 thousand ,000 years ago, suggesting that the ancestor to all males derived during the very early evolution of modern humansrather than within a much later sub-population. Central to Western Africa seem to be the regions where this early human ancestor influenced subsequent populations. For genetic Eve, or the most recent common matrilineal ancestor Mitochondrial DNA for all humans, is harder to specify, where the dates can range between more than 120,000 years ago. There were likely many female genetic lines but Mitochondrial Eve likely became the only female line. All of these early dates suggest greater human diversity and variation were originating in Africa, long before migrations began to significantly shape subsequent human populations in other parts of the Earth.<ref>For more on genetic Adam and Eve, see: Callaway, E. (2013) Genetic Adam and Eve did not live too far apart in time. <i>Nature.</i> [Online] Available from: doi:10.1038/nature.2013.13478 [Accessed: 12 June 2017].</ref>

As stated, for most human populations, the vast majority of it can be traced to a large wave of migrations that occurred between 80-50 thousand years ago. Overall, humans are about 99.5% similar to each other, suggesting that relatively few populations have influenced the vast majority of our genetic makeup. In Africa, using linguistic and genetic evidence, there were likely about 14 main population groups. These groups show a wider range of genetic variability than many other populations throughout the Earth, which suggests that humans spent a lot of time in Africa before they successfully spread and colonized the remaining parts of Earth (Figure 2). Modern African populations in eastern Africa, between Namibia and South Africa, are likely the most similar to other human populations, which suggests that it was this region that modern humans began the large, second wave migration(s) that eventually colonized the rest of the planet. <ref>For more on the great migration that have subsequently influenced human populations, see: Yotova, V., Lefebvre, J.-F., Moreau, C., Gbeha, E., et al. (2011) An X-Linked Haplotype of Neandertal Origin Is Present Among All Non-African Populations. <i>Molecular Biology and Evolution</i>. [Online] 28 (7), 1957–1962. Available from: doi:10.1093/molbev/msr024.</ref>