ROCHE GENE-SEQUENCING METHOD ABUNDANCE of antibiotic-resistant genes (as a percent of all genes detected from a specific habitat) DIVERSITY of antibiotic-resistant genes (as a percent of 2,999 known antibiotic-resistant genes) SANGER GENE-SEQUENCING METHOD Arctic snowChicken gutHuman fecesOceanSoil Antarctic lakeDeep oceanHuman fecesMouse gutOceanSedimentsAirTreated sewage sludgeFarm soil 0% 5% 10% 15% 20% 25% 30% HABITAT OF BACTERIA* *Selected readings typical of those found in the study

SOURCE: “Large-Scale Metagenomic-Based Study of Antibiotic Resistance in the Environment,” Current Biology.