Bistability in Biological Systems
James Ferrell characterized bistable switches in cell signaling and cell cycle. Michael Elowitz constructed synthetic genetic toggle switches demonstrating bistability in engineered circuits. Developmental biologists recognize bistability as fundamental for cell fate decisions—mutual inhibition between transcription factors creates stable alternative states.
Morphogen Gradients in Development
Lewis Wolpert proposed the French flag model explaining how concentration gradients specify positional information. Christiane Nüsslein-Volhard and Eric Wieschaus discovered Drosophila patterning genes earning the 1995 Nobel Prize. Developmental biologists characterize morphogen gradients in diverse organisms. Alexander Turing mathematically modeled reaction-diffusion pattern formation.
Maternal Effect Genes in Drosophila
Christiane Nüsslein-Volhard and Eric Wieschaus discovered maternal effect genes through systematic mutagenesis screens earning the 1995 Nobel Prize. Wolfgang Driever and colleagues characterized Bicoid as morphogen. Developmental geneticists study how maternal contributions initialize embryonic patterning across species.
Gap Genes and Embryonic Segmentation
Christiane Nüsslein-Volhard and Eric Wieschaus identified gap genes through systematic screens finding mutations deleting large embryonic regions. Hunchback, Krüppel, Knirps, and Giant represent major gap genes. Developmental biologists study gap gene cross-regulation creating broad regional domains. Mathematical biologists model gap gene network dynamics.