Compare and contrast the out-of-Africa model and multiregional theories of the origin of modern man. Which theory is supported by the preponderance of genetic evidence? What type of evidence supports the other theory

Question

What will be an ideal response?

Answer 1

The multiregional model: Originally, there were two opposing views on how and where our species originated. One school of thought used fossil evidence to argue that after leaving Africa, members of the genus Homo formed a network of interbreeding populations that gradually transformed into our species, H. sapiens. This model favors evolution and transition within the genus Homo.

The out-of-Africa model: The other school of thought used a combination of genetic and fossil evidence to argue that our species originated in Africa between 200,000 and 100,000 years ago. The genetic evidence shows that small groups of H. sapiens spread from Africa by about 60,000 years ago and replaced earlier populations of other human species, including H. erectus and Neanderthals (H. neanderthalensis), and perhaps H. floresiensis, driving them into extinction. This model favors speciation in Africa, followed by migration and replacement of other species.

The evidence now overwhelmingly supports the out-of-Africa model, identifying southwestern Africa as the most likely place where modern humans originated and East Africa as the point of migration from Africa. According to this model, modern human populations are all derived from a single speciation event that took place in a restricted region within Africa. As a result, the human populations who remained in Africa have the highest degree of genetic diversity, and all populations outside Africa show a high degree of genetic relatedness because they are derived from the relatively small migrant population.