The scientists examined the DNA of mitochondria, tiny power plants within cells that get passed down from mother to child. Scientists use mitochondrial DNA from living populations to decipher ancient movements of their ancestors. Most studies have examined only a small part of the mitochondria's circular piece of DNA. But Antonio Torroni, a geneticist at the University of Pavia in Italy, and his coauthors compiled complete mitochondrial genomes from 41 native North Americans and combined that data with information from previous studies... supports the widely accepted notion of an initial coastal migration wave. A second wave of migration probably left...