They sequenced the genomes of 15 ancient humans, who came from sites ranging all the way from Alaska to Patagonia. One person from Spirit Cave in Nevada and five from Lagoa Santa in Brazil were especially instructive. They were all just over 10,000 years old, and though they lived 6,300 miles apart, they were strikingly similar in their DNA. Genetically, they were also closely matched to Anzick-1—a famous Clovis infant from Montana, who was about 2,000 years older.

Further investigation will be required on this...

All this suggests that, about 14,000 years ago, the southern lineage of early American Indians spread through the continent with blinding speed. To picture their movements, don’t think of a slowly growing tree, incrementally sending out new branches and twigs. Instead, imagine a starburst, with many rays zooming out simultaneously and rapidly.

Unlikely.