New tools of genomic analysis are being used to shed light on historical puzzles. Migrations of ancient peoples, the effects of geographic boundaries on human movements, origins of ethnic groups, and racial differences are now the focus of integrated analysis by historians, anthropologists and geneticists. "When people move, they take their genes along and pass them on to their descendants in their new homes," Dr. Mary-Claire King states. "Thus, every present-day population retains clues to its ancient roots. Common ancestries can be confirmed and human migrations traced by comparing DNA sequences of present-day populations." From the Series:Science Forum