James Kling | May 11, 1997 | 9 min read
Biologists are constantly seeking more sensitive assays to detect the presence of organisms or telltale DNA, RNA, and proteins. Although radioactive tags incorporated into the target itself (or into a complementary strand)-and later detected by Geiger counters or film exposures-have traditionally given good sensitivity, the problems of waste disposal and laboratory monitoring have driven a search for alternative tags that have radioactivity's sensitivity but avoid its hazards. Fluorescent tags-