1971 – 1996 | Professor of Molecular Microbiology

Werner Arber is a pioneer in molecular biological research and made groundbreaking contributions to molecular biology through his discovery of the restriction enzymes. With his discovery of the bacterial restriction enzymes, molecular scissors for genes, he not only laid a foundation for today's molecular biology, but also paved the way for various research areas at the Biozentrum. This contributed greatly to the internationally renowned reputation of the Biozentrum. In 1978, Werner Arber was awarded the Nobel Prize for Physiology or Medicine together with the Americans Daniel Nathans and Hamilton Smith for the discovery of restriction enzymes and their applications to problems of molecular genetics (https://www.nobelprize.org/prizes/medicine/1978/summary/). As professor of Molecular Biology from 1971 to 1996, Werner Arber was one of the founding professors of the Biozentrum, active in research, teaching and leadership.

Discovery of restriction enzymes and studies on microbial evolution
In the 1960s, Werner Arber's research was focused on bacteriophages. He studied how these viruses infect bacteria and how bacteria protect themselves against such invaders. Arber found that bacteria possess molecular defense systems based on specialized enzymes cutting foreign DNA at precise sites. These molecular scissors in bacteria, so-called restriction enzymes or restriction endonucleases, recognize foreign DNA molecules and cut them at specific points. As endogenous function in bacteria, these enzymes help e.g. to defend viral infections, by destroying foreign genetic material into harmless fragments. Later, Arber also discovered that bacteria have protective mechanisms that prevents the cell's own DNA from being destroyed. For example, specific enzymes modify their own genetic material by attaching certain chemical groups, thereby protecting it from being accessed by restriction enzymes.

The discovery of restriction enzymes not only provided insight into the mechanisms of microbial immunity but also enabled their use as invaluable tools to study and specifically manipulate DNA. It transformed biology into a molecular and engineering science. By allowing DNA to be reproducibly cut into defined fragments, Arber’s work laid the foundation for recombinant DNA technology. In basic science, the discovery of restriction enzymes made it possible to investigate individual genes and their function and recombine selected DNA segments for the first time. The discovery of restriction enzymes enabled the creation of genetically modified organisms, the development of new medicines, major advances in agriculture, and biotechnology. Arber's findings were also essential for later achievements such as the Human Genome Project, which relied on restriction enzymes to map and analyze genomes. Overall, these important findings, which were honored by the Nobel Prize Committee, led to a leap in genetic engineering research and a better understanding of the molecular evolution of organisms.

In later years, Arber also studied mechanisms of microbial evolution, proposing that molecular processes drive genetic variation and adaptation for evolution. Specifically, he studied how the bacterial genome is reshaped through mechanisms including genetic recombination, mobile genetic elements (e.g. transposons) and horizontal gene transfer. Through these mechanisms, organisms can acquire new or modified genes or variants thereof to facilitate adaptation to selective pressures, thereby playing important roles in evolution. Arber proposed that evolution is not just a product of random mutations filtered by natural selection, but also involves inherent molecular mechanisms within organisms that generate diversity in structured ways. Arber sometimes described this as an “inbuilt potential” of living systems, meaning that life has self-organizing genetic processes that naturally foster evolutionary change. In this context, Arber also stressed the importance of maintaining the large global gene pool as substrate for future evolution.

Contributions to science community
Werner Arber was born in 1929 in Gränichen in the canton of Aargau, Switzerland. He studied chemistry and physics at ETH Zurich and received his PhD from the University of Geneva in 1958. After conducting research at the University of South California in Los Angeles, USA, he was appointed group leader at the University of Geneva in 1960 and promoted to Professor of Molecular Genetics in 1965. From 1971 to 1996, Werner Arber was Professor of Molecular Microbiology at the Biozentrum, University of Basel. In 1978 he was awarded the Nobel Prize in Physiology or Medicine. Arber also engaged deeply in bioethical discussion and served in prominent roles in science policy and education. Between 1986 and 1988 he was also rector/president of the University of Basel. For many years, he was a member and vice president of the Swiss Science Council and from 1996 to 1999 president of the International Council of Sciences ICSU. Most recently, he served as President of the Pontifical Academy of Sciences (2011 to 2017), an important international discussion forum for science and its implications for society. Arber always emphasized the importance of basic research, highlighting how discoveries made in the pursuit of fundamental knowledge often lead to transformative technologies. Arber’s legacy is that of a scientist whose curiosity-driven research not only reshaped genetics but also profoundly influenced society at large.