ADELAIDE, AUSTRALIA—The Atlantic reports that researchers are using plaque from the teeth of ancient Polynesians to track prehistoric human migrations in the Pacific. University of Adelaide biologists Laura Weyrich and Raphael Eisenhofer collected samples of plaque from the uncleaned teeth of skulls stored in a number of museums. The samples contained the DNA of a number of common mouth bacteria and by studying the mutations in these bacteria’s genes, the team hopes to be able to infer the timing and exact routes of several migration events. “The traditional means of looking at human migrations might be too coarse,” says Eisenhofer. “Hopefully, the rapid rate of evolution in that bacteria will allow us to answer some of the questions.” To read in-depth about ancient microbial DNA, go to “Worlds Within Us.”