DNA uncovers mystery migration to the Americas
bbc.com
bbc.com
A lot of research like this makes an assumption that the genetics of modern native americans are close to pre-columbus genetics but that is almost certainly not the case.
When I was in graduate school I got a smithsonian fellowship to study the feasibility of amplifying dna from pre-columbus incan bones (they left their dead above ground on a plateau and so no contamination from tannins from the soil). I showed the dna could successfully be amplified.
I then left science and I'm not sure where the research went after that.
Previous data on the matter:
https://en.wikipedia.org/wiki/File:Migraciones_austronesias....