Human remains more than 12,000 years old have been found in half a dozen locations across North America. At Hoyo Negro in Mexico a convergence of genetic and skeletal evidence suggests the first people in the new world originated in Siberia, not elsewhere as some have theorized, and that they are related to modern Native Americans. How they arrived remains an open question.
Around 12,000 years ago an ice- free corridor was open between the two large ice sheets that covered much of North America. But archaeological evidence suggests people were here as early at 16,000 years ago. They may have found their way to the Americas by following a coast route. The fact that paleo-Americans seemed to look different than modern native Americans can be attributed to a genetic shift in the population over time rather than to one population group replacing another.