Researchers even injected four healthy volunteers--yes, human volunteers--with low doses of bacterial toxins to monitor gene response. Then they compared this with genetic data from mice they afflicted with similar troubles. By the end of the study, the researchers looked at some 5,000 genes that overlap humans and mice. The genetic changes similar in both people and mice barely hit the 50 percent neighborhood, which is like random chance. One gene activated in mice, were not even expressed in humans. Another gene that helped mice recover, harmed humans.