What happens to the main race of Adam after Genesis 12?

Les explains that after the Tower of Babel, with the confusion of tongues and the sorting of world population through Noah’s three sons, Genesis 12 is where God lets the main race of Adam continue on like a river. That main race becomes what is now referred to as the Gentile people or nations, continuing like a mass river, illustrated by the old Mississippi finding its way to the Gulf. Out of that polluted river of the one race of Adam, God pulls one man, Abram, and from him comes the nation of Israel, the Jew. God deals with this nation peculiarly and particularly, usually Jew only, with exceptions. From Genesis 12 through the Old Testament, God is dealing with Israel, but there are exceptions, such as sending Jonah to the Gentile city of Nineveh.