Douglas A. Lockard · CC BY-SA 3.0

Walter Gilbert helped invent chemical DNA sequencing, developing the Maxam-Gilbert method with Allan Maxam that let scientists read genetic code directly for the first time — work that shared the 1980 Nobel Prize in Chemistry with Frederick Sanger and Paul Berg. He coined the terms "intron" and "exon" to describe the structure of genes, later proposed the RNA world hypothesis for the origin of life, and moved from Harvard into industry, co-founding Biogen and Myriad Genetics. He was an early and vocal champion of sequencing the entire human genome.