Further back than that, the tribes as we know them certainly did not exist, and any persons here were just as likely to be of some completely unrelated race, possibly just exploring here, and not even of the Red Indian race at all.
All of this crap about Asia is simply to avoid bringing the whole weight of the Bering Strait establishment down on their heads at one time. There is no serious possibility that this skeleton is racially Asiatic, indeed the Ainu are not racially Asiatic. This is a Europoid skeleton pure and simple.
Their imposition upon these remains is literally sacrilege.