Edward Lawrie Tatum was an American biochemist who along with George Wells Beadle won the 1958 Nobel Prize in Medicine for showing that genes control individual steps in metabolism. Born in Colorado, initially, he followed his father’s footsteps to study chemistry at the graduation level; then took up microbiology for his postgraduate degree and biochemistry for his PhD. His hybrid educational qualifications later affected his career. Nonetheless, his talent was recognized by his professors, who recommended him to Professor Beadle, while he was working on Drosophila at the University of Stanford. Afterwards the two scientists worked on Neurospora and established the ‘one gene – one enzyme’ theory, which earned them their Nobel Prize. Meanwhile Tatum had to leave Stanford because he was an Assistant Professor in the Biology department with a degree in chemistry. Subsequently, he shifted to University of Yale as Assistant Professor in Botany and began working on bacteria with another Nobel winning scientists Joshua Lederberg, whom he had also mentored. Subsequently, they established that E-coli bacteria entered a sexual phase, during which it could pass on genetic information. At last the University of Stanford invited him back as a full professor at the Department of Biology. Later, he held many important positions and served in different capacities till his death.