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North America's only living native marsupial, the Virginia Opossum, is portrayedby San Francisco Bay artist Pat Sherwood. Marsupials lay at the center of a fundamental problem in mammalian taxonomy-- the sister relations of egg-laying, marsupial, and placental mammals. In this issue, Killian et al. provide the first sequence data from a large nuclear gene that reconcile genetic, epigenetic, and morphology based predictions of higher-order mammalian phylogeny.