Karl Deisseroth, Peter Hegemann and Georg Nagel are announced as the winners of the 2026 Nobel prize in physiology or medicine by Nobel committee secretary general Thomas Perlmann

Jonathan Nackstrand/AFP via Getty Images

The 2026 Nobel prize in physiology or medicine has been awarded to Karl Deisseroth, Peter Hegemann and Georg Nagel for the development of techniques for controlling genes with light, known as optogenetics. 

“It’s a really new era in neuroscience thanks to this methodology,” said Thomas Perlmann, secretary general of the Nobel committee. 

In the 1990s, Peter Hegemann, then at the Max Planck Institute for Biochemistry in Germany, wondered how a single-celled alga, Chlamydomonas, can swim towards light. 

In the 2000s, he and Georg Nagel, then at the Max Planck Institute for Biophysics in Frankfurt, Germany, discovered that the key to this is a light-sensitive protein that acts as a switch, opening a channel that lets ions flow through the protein when exposed to light. The protein was called channel-rhodopsin. 

Karl Deisseroth, at Stanford University, then genetically engineered rats to produce channel-rhodopsin in their nerve cells, meaning specific nerves could be activated by shining light on them. This work, published in 2005, enabled researchers to study the function of specific groups of neurons and is now widely used worldwide.  

More light-sensitive proteins have since been discovered, which respond to different colours, enabling even more precise control of engineered nerve cells.  Therapies based on optogenetics are also being developed. For instance, it is being explored as a way to restore some sight to people who are blind. 

The downside of optogenetics is that light cannot penetrate far into the body. So several groups around the world are trying to develop equivalent methods based on ultrasound or magnetism.