Researchers have compiled the first genome sequences of desert pupfish from the American Southwest, including the unique Devils Hole pupfish. The genomes of the 8 Devils Hole pupfish sequenced contained an amazing number of identical stretches of DNA, amounting to 58% of the genome -- among the most inbred of any known vertebrate. Paradoxically, of 15 gene deletions, five involved adaptation to hypoxia, or low oxygen levels, which are characteristic of the pupfish's habitat.