Final answer:
The Out of Africa theory suggests that humans descended from Africa, supported by genetic research. There are different theories on migratory pathways out of Africa, but more research is needed to confirm them.
Step-by-step explanation:
The Out of Africa theory suggests that humans most likely descended from Africa. This theory is supported by genetic research that found a close genetic relationship between humans outside of Africa and those in Africa. The genetic variance found in Africa was not found in the rest of the world, further supporting the theory.
There are several theories on the migratory pathways out of Africa, with one suggesting that Homo ergaster migrated northward into Eurasia around 1.75 million years ago. Another theory proposes an earlier migration around 2 million years ago, leading to the population of Dmanisi hominins settled in eastern Europe by 1.85 million years ago. However, more research is needed to confirm these theories.