But the next time you're making that mouth-watering salad, think twice before you load up on the alfalfa sprouts. And since sprouts aren't commonly cooked, there's no step to kill the harmful bacteria. If the work of UGA researchers pans out, fish could soon replace, or at least supplement, mice for screening chemicals in the lab. A team of toxicologists has transferred genes from bacteria into the Japanese medaka, a tiny freshwater fish previously used for cancer research, to help evaluate the genetic health risks of chemicals in the environment. Experimenting on fish is cheaper than on lab mice, says Winn, and less sensitive, politically.
Transgenic fish offer nearly every kind of exposure route as mice.
Transgenic fish carry specific DNA sequences that serve as targets for DNA damage or mutations. Researchers expose the fish to a potential contaminant, then analyze tissues for mutations in the indicator bacteria. Because the same detection system is used in lab mice, Winn said comparative studies are currently possible using two different species. Fish can be used for screening organic materials such as PCBs, as well as heavy metals, radiation, herbicides and pesticides. They are especially useful, Winn said, in toxicity screening the more than 2,000 new chemical compounds introduced in the market each year.