Water flea’s 31,000 genes top humans

The animal with the most genes—about 31,000—is the water flea, a near-microscopic freshwater crustacean. By comparison, humans have about 23,000 genes.
Water vision
“We were surprised to find the incredibly high level of complexity of the set of Daphnia vision genes,” says co-author Todd Oakley, an associate professor at the University of California, Santa Barbara. Oakley’s team focused on vision genes in the tiny creature.

“While humans have four light-sensing proteins (opsins), the Daphnia genome has 46 opsins,” says Oakley. “A possible explanation for this complexity is that Daphnia use these genes to understand the complex light regime of their aquatic environment.”