One of the most significant complications came from the growing evidence for pre-Clovis human presence in the Americas — evidence that, taken together, argued convincingly that people had been in the Americas well before the Clovis horizon.

The White Sands footprints in New Mexico, eventually dated to approximately 21,000 to 23,000 years ago, represented the most dramatic demonstration of this pre-Clovis presence, but they were not alone.

Monte Verde in Chile, the Paisley Caves in Oregon, Meadowcroft Rockshelter in Pennsylvania, the Friedkin site in Texas, and other sites collectively painted a picture of human presence in the Americas that predated Clovis by thousands of years.

If people were in the Americas before Clovis, what was their relationship to the Clovis people and to the people represented by Anzick-1?