51.   While scientists have been studying the MHC for years, the new work shows the region contains more genes than previously thought, Branscomb said.

52.   The new corn, developed by Swiss drugs company Ciba-Geigy, contains a gene which is resistant to antibiotics.

53.   The third chimp was not injected with the virus and the fourth one was given a vaccine that did not contain genes from the AIDS virus.