Barbara McClintock Discovers Transposable Elements

Cytogeneticist Barbara McClintock identified that genetic elements she named Dissociation and Activator could change position within maize chromosomes, a phenomenon she termed transposition. Working at Cold Spring Harbor Laboratory, she observed that these mobile elements controlled gene expression by inserting near other genes, producing the mosaic color patterns visible in maize kernels. Her findings, published in 1950, were largely dismissed for decades. She received the Nobel Prize in Physiology or Medicine in 1983, thirty-five years after the discovery.