Question About Civilization Cradles?

  I know there's the Four Traditional Cradle of Civilizations such as Egypt, Mesopotamia/Sumer, Indus Valley and the Yangtze Yellow Rivers in China.  Recently the Andes and Meso-America have been added to that list. I wonder if the Mississippians, the People living along the Niger river and the Sahel and the people of Ethiopia could one day be added to that list