No one knows exactly the population of Native Americans when contact with Europeans occured. There are some estimates claiming there were 18 million in North America and upwards to 40 million in the combined continents. It’s estimated that the population in the Americas dropped by almost 90% within a few hundred years after the arrival of the Europeans.

Up until last week we also didn’t really have a great grasp on the minimum number of migrants from Siberia that peopled the Americas. However, we now know how many people came over from Siberia… About 250, thanks to work by Michael Crawford, a University of Kansas anthropological geneticist who helped calculate the size of the original founding population of the Americas.His study was published last week week in the journal Genetics and Molecular Biology.

He and his colleagues sequenced DNA from the nine independent, noncoding regions of the genomes from indigenous peoples distributed from China to South America spanning over 15,000 years. Based on 100 million generations, they then calculated the founding populations by isolation-with-migration computer simulation model. Each conclusion revealed founding groups were between about 229 to 300 people. Which led the group to estimate the parameter for the original founding population of Native Americans of about 250 people.

Why is this important? Well, recognizing the size of this genetic bottleneck during the populating of the Americas is important for determining the extent of genetic markers needed to characterize Native American populations in genome-wide studies and to evaluate the adaptive potential of genetic variants in this population.