When did the mixing between East Asian and Ancient North Eurasian populations occur?

Where did it occur — in eastern Asia, in Beringia, or in multiple locations?

How many distinct founding migrations were there, and what were the relative contributions of different source populations to the ancestry of different contemporary Native American groups?

These questions are still being actively researched.

The development of the ancient DNA record — the analysis of additional ancient genomes from Siberia, Beringia, and the Americas — has provided additional data points that constrain the possible models.

Each new ancient genome adds information that helps narrow the range of possibilities.