Scientists have discovered that the original Americans descended on the North American continent from neighboring Siberia in a single wave 23,000 years ago at the most — right when the last Ice Age was at its peak.

These Native Americans probably spent most of their time in the north of the country, where they stayed for perhaps thousands of years before separating into two distinct populations: one in North America, and the other heading into the jungles of South America, according to an Associated Press report.

These findings, published this week in the journal Science, settles a big debate on how Native Americans got here, and eliminates some other popular theories that there was a wave of people that came from East Asia before the Ice Age set in.

The findings also shoot down a theory that there were multiple waves independent of each other that resulted in different subgroups of Native Americans, as we see today, but as it turns out it was most likely one big group that eventually splintered over time.

Researchers thing the original Americans got here through a land bridge that had formed between Siberia and Alaska during the Ice Age. The Inuits and Eskimos that reside in frigid northern Canada were believed to have arrived later.

It also eliminates the proposed idea that it was Polynesians or Europeans that could have contributed their own genetics to Native Americans.

A research team from the University of California at Berkeley made the findings. They used three different statistic models to come to their conclusions — two from their own university, and one from the Wellcome Trust Sanger Institute in England. The three models agreed with each other independently.

The data used sequenced genomes from 31 living Native Americans, Siberians, and people from other areas that may have resulted in the migration, including the Pacific Ocean region. They also used genomes from 23 ancient individuals from North and South America.