Tracing ancestry in DNA
who : well
what : A coastal route would have been the easiest way in, But if still would have been a hell of a trip.
where : Americas
whom : About the same time as modern humans pushed into Europe, some of the same group that had paused in the Middle East spread east into Central Asia, where they eventually reached as far as Siberia, the Korean peninsula, and Japan.
how : Once across, they followed the immense herds of animals into the mainland and spread to the tip of South America.