A tiny, yet surprisingly complex source is helping Ellen Pritham break genetic ground. The biology assistant professor was part of an international team that mapped the DNA code of the water flea, Daphnia pulex, making it the first crustacean genome to be sequenced. The researchers found that the Daphnia pulex genome held more genes—about 31,000—than any animal ever sequenced; by comparison, humans have about 20,000 genes. The team believes that many of the new genes may enable the organism to respond to its changing environment. The Daphnia will thus serve as a model for a new field, environmental genomics, in which scientists aim to better understand how genes and the environment interact. The work of Dr. Pritham’s team has been featured in Science and Nature magazines.