ABSTRACT
Genetic mechanism s mus t als o exis t tha t regulat e w h e n an d i f a gen e i s
expressed an d t o wha t extent .
I n thi s chapte r w e firs t discus s th e bette r understoo d prokaryoti c regula -
tory mechanism s an d follo w thi s wit h a brie f consideratio n o f th e les s wel l
understood an d mor e comple x eukaryoti c regulatory mechanisms .
