So where did these people go and where did the modern tribes come from? They weren't related, it seems.
The old mtDNA pattern is still there, but it has been partially or mostly swamped out by more recent or more numerous arrivals.
There were probably two or more early coastal migrations, bringing at least haplogroups D and A. Another form of D, along with B and C, seem to have come later.
The second D, along with B and C, may have come via the land bridge through central Canada. They had an adaptation which let them spread rapidly in terrestrial habitats, while the coastal dwellers had an adaptation which kept them close to the coast.
The National Geographic DNA map I linked in post #10 show the following DNA groups in the Americas = A, B, C, D, M3, M217 and X.