The humble zebrafish, a popular aquarium pet, has become a pin-up for scientists researching human diseases.
Despite sharing a common ancestor with humans around 450 million years ago, zebrafish are biologically quite similar to us. Indeed, 84 percent of genes known to be associated with human disease have a zebrafish counterpart.
Since zebrafish were first cloned in 1981, scientists have introduced human diseases into the fish and tested the impact of thousands of potential drugs. The tropical freshwater fish are robust, cheap, grow at an astonishing rate and are used in almost every area of medical research.
More than 880 laboratories around the world use zebrafish and they have even been sent into space in the name of research.