The founding of South America appears, on current evidence, to have occurred relatively quickly after the entry into the Americas from Beringia — with ancestral South American populations diverging from ancestral North American populations at a time that genetic models place somewhere between 16,000 and 20,000 years ago, though the uncertainty in these estimates is substantial.

The rapid dispersal of people across South America after this founding event is reflected in the genetic record as a pattern of rapid differentiation of regional populations, with different groups in different geographic areas accumulating distinct genetic profiles through the combined effects of local population dynamics and limited gene flow between regions.

On top of this early differentiation, the genetic record shows evidence of subsequent contact and gene flow — episodes in which populations that had previously diverged came back into contact and mixed.

The timing and geographic pattern of these contact episodes is complex and varies across the continent.