Native Americans, Egyptians, Jews and everyone else are all descended from Adam and Eve. In fact, we’re all descended from the family of Noah, who were the only survivors of the flood (1 Peter 3:20).
God divided the nations of the world soon after the flood (Genesis 10:32). The rationale for this arose from the building of the tower of Babel, where
the Lord confused the language of all the earth. And from there the Lord dispersed them over the face of all the earth. (Genesis 11:9)
National groups would quickly form among the families that spoke the same language. Since marrying close relatives was not disapproved of at the time, and since close relatives were now the only people who spoke the same language, there would be few marriages outside the family group. Nations would thus develop a genetic identity and distinctive features such as skin colour. Any emerging genetic differences would combine with the language barrier and the distance between nations settling ‘over the face of all the earth’ to prevent them all merging back into one people again.
In Christ Jesus, people from all nations can still be gathered together into one, though — part of the family of God that extends across all nationalities (John 11:51-52; Galatians 3:26-28).