When people migrate, Canis familiaris travels with them. Piecing together the details of those migrations has proved difficult because the clues are scattered across the genomes of hundreds of dog breeds. However, in a study published April 25 in Cell Reports, researchers have used gene sequences from 161 modern breeds to assemble an evolutionary tree of dogs. The map of dog breeds, which is the largest to date, unearths new evidence that dogs traveled with humans across the Bering land bridge, and will likely help researchers identify disease-causing genes in both dogs and humans.