Final answer:
Modern humans are more closely related to each other than to Neanderthals or Denisovans, with their divergence from Neanderthals estimated at about 600,000 years ago, supporting the 'Out of Africa' model of human origin.
Step-by-step explanation:
Modern humans from various regions such as Europe, Africa, Asia, America, Australia, and Oceania are more closely related to each other than any is to Neanderthals or the Denisovans; the estimated divergence of Neanderthal to modern humans is about 600,000 years ago. This evidence supports the “Out of Africa” model.
Out of Africa Model
- The “Out of Africa” model theorizes that all modern humans emerged first in Africa roughly 200,000 years ago and subsequently expanded out of Africa around 100,000 years ago, subsequently replacing all other human species. Research has shown that human genomes from outside of Africa share close ties with those inside Africa, suggesting a common point of descent. Furthermore, genetic variance found within Africa that is not present elsewhere supports the idea that the genetic diversity of present-day humans originates largely from an African lineage.
Neanderthal Genome Insights
- Studies of the Neanderthal genome, particularly the work of Richard E. Green and colleagues, have shown that the Neanderthal genome shares 2 to 3 percent greater similarity with people living outside Africa than with people in Africa, indicating some level of interbreeding between Neanderthals and early modern humans as they migrated from Africa. This interbreeding likely occurred before the divergence of various contemporary human populations such as Europeans, East Asians, and Papua New Guineans.