For years, the favored recipe for making a modern European was this: Start with DNA from a hunter-gatherer whose ancestors lived in Europe 45,000 years ago, then add genes from an early farmer who migrated to the continent about 9000 years ago. An extensive study of ancient DNA now points to a third ingredient: blood from an Asian nomad who blew into central Europe perhaps only about 4000 or 5000 years ago. This third major lineage originated somewhere in northwestern Asia, perhaps on the steppes of western Asia or in Eastern Europe. This is a "ghost lineage," because no pureblood member of this group survives today. But whoever these people were, their descendants successfully spread far and wide, for their genes show up not only in Europeans but also in Native Americans, according to a talk by paleogeneticist Johannes Krause of the University of Tübingen in Germany, who spoke at a biomolecular archaeology meeting last week. Those who heard the talk in a packed auditorium at the University of Basel were impressed by the genomic data's high resolution—it is the largest data set of ancient DNA ever presented in a single study—even though some aren't convinced about the exact details.