Born on March 21, 1932 in Boston as the son of an economist teaching at Harvard University, Walter Gilbert majored in physics, graduating as a B.Sc. emeritus in 1953 and obtained his master’s degree in 1954. In 1957, he was awarded a Ph.D. in mathematics at Cambridge University. Following a post-doctoral fellowship and after working for a year as a research assistant to the physicist Julian Schwinger (1965 Nobel Prize), both in Harvard, Gilbert was appointed Assistant Professor at the Department of Physics there in 1959.
His acquaintance with the molecular biologist James Watson (1962 Nobel Prize for Medicine) inspired Gilbert to move away from elementary physics and to study the elementary building blocks of organic life. Asked by Watson to help him isolate an unstable nucleic acid called mRNA, which was thought to act as a carrier of genetic information, Gilbert soon developed into one of the most outstanding experts in the field of molecular biology. In 1964, he moved to the Biophysics Department as an Assistant Professor. In 1968 he was appointed Professor for Biochemistry and became an American Cancer Society Professor of Molecular Biology in 1972.
After much varied and successful research, Walter Gilbert was awarded the 1980 Nobel Prize for Chemistry together with the biochemists Frederick Sanger (GB) and Paul Berg (USA). The three scientists received their prize for their fundamental studies in the field of genetic surgery. Gilbert and Sanger developed, independently of one another, methods for determining the exact sequence of nucleic acids in deoxyribonucleic acids. Gilbert and Sanger used restriction enzymes to dissect the DNA double helix into smaller parts and marked the ends radioactively. Following further dissection, the researchers obtained so-called sub-fragments. The molecular elements were then broken down even further using chemical degrading solutions.
Finally, they were able to determine the exact position of each nucleic acid. Thanks to Gilbert’s method, it is possible to pinpoint the positions of the 100,000 to 200,000 human genes in the DNA strand exactly and to find out what their composite molecular sequences are. By automating this “gene sequencing” process, scientists are now able to analyse not just single genes but entire human chromosomes consisting of between 2000 and 5000 genes. Since 1974 Gilbert has been an American Cancer Society Professor of Molecular Biology.
By Volker Steger
These days Walter Gilbert is very much an artist, he has his own studio and and his work is exhibited. His choice of colours and the precise execution of his sketch reflect this.
But when he suddenly takes out his smartphone and starts to look up various webpages, it becomes clear that scientific detail matters, too:
„I'm trying to find you the original DNA sequence we used for the sketch! But I can't find it... So, this is just some sequence...!“
Experimenting with Beauty
by Adam Smith
Wally Gilbert’s drawing depicts a discovery, but not the one for which he received his Nobel Prize. That Nobel Prize-awarded work, the development of a rapid method for sequencing DNA, helped drive the growth of modern biology. But here Gilbert has chosen to focus on an earlier piece of work of which he is more proud. “DNA sequencing is a technical invention that makes something possible, but doesn’t have any deeper meaning in its own right,” he says. In contrast, the discovery he symbolically illustrates here was one that truly increased our understanding of how biology worked.
In the mid 1960s, one of the critical questions being asked by biologists was how genes are controlled. Why do genes turn on in one cell and not in another? An answer to the problem had been proposed by François Jacob and Jacques Monod, who had themselves received the Nobel Prize in 1965. They suggested that genes were regulated by other genes, the presence or absence of the product of the second gene controlling the activity of the first. Gilbert’s illustrated discovery demonstrated that they were right.
The blob-like object represents a protein, called the lac repressor. As the arrow shows, it is about to interact with a stretch of double-stranded DNA. When the protein binds to the DNA, it blocks the synthesis of the enzymes that digest the sugar lactose. But when lactose enters a cell, it causes the lac repressor to separate from the DNA, allowing the gene to function normally. This very first demonstration that a protein could bind to a DNA sequence paved the way to our current understanding of the control of genes by transcription factors.
Gilbert is unusual, but not unique, in his interpretation of Volker Steger’s instructions. But he is certainly the only Laureate among the Volker’s ‘sketchers’ who is now a professional artist! “I’m mostly a photographic artist,” he explains, “And I do the art as an experimenter. I create an image by experimentation rather than by design, and there’s a similarity to the experimental side of science in which you’re dealing with a world where you go and you experiment with it to see what you learn, and you alter it by experiment. There’s an underlying similarity … the drive to create something new, the creation of a novel image in the art and the creation of a novel idea in the science.”