Scientists came up with an explanation for why (Americas) Indians and Asians both had mostly straight
dark hair, a land bridge. A few hundred years before they came up with the land bridge, they didn't
even know that the New
World existed, and they already have an explanation for something like that. At one time, humans were all
one people from the same place (before the continents became different continents), in that sense, (Americas) Indians and Asians come from the same place. Otherwise, there's not much connection.
Sure, at one time the land might have stretched out between two different lands like dough before the sea washed it away, but there's also a lot of other things that could have happened. The land bridge is just
one attempt to explain it, which is why science is meant to be taken with a grain of
salt (even science related to the
coronavirus).