Migrationism As The New Paradigm

Dienkes' does a nice job at his blog summing up a paradigm for the nature of prehistoric population genetic change under the rubric "migrationism" even if his portrayals of the alternatives are to some extent straw men. In his definition of migrationism:

Migrationists adhere to an older and much-maligned arrows-on-the-map paradigm, whereby humans intentionally decide to move from A to B, even across great distances. According to this idea, colonists sometimes mix with/sometimes kill/sometimes avoid pre-existing inhabitants. Migrationists predict that prehistoric Europe was a dynamic patchwork of genetic-cultural units entering the continent from different routes at different times, gradually forming the cornucopia of its proto-historical ethnic groups.

He goes on to sum up the discoveries, many involving ancient DNA, that support this paradigm relative to the alternatives.