2007 Nobel Prize in Physiology or Medicine: Knockout Mice

The winners of the 2007 Nobel Prize in Physiology or Medicine were announced this morning. The prize went to Mario R. Capecchi (University of Utah), Martin J. Evans (Cardiff University), and Oliver Smithies (UNC), all for their work contributing to knockout (and knock-in) mice becoming one of the most powerful scientific tools available to biologists today. Or, in the less inspiring Nobel-speak, "for their discoveries of principles for introducing specific gene modifications in mice by the use of embryonic stem cells."

From the official press release:

This year's Nobel Laureates have made a series of ground-breaking discoveries concerning embryonic stem cells and DNA recombination in mammals. Their discoveries led to the creation of an immensely powerful technology referred to as gene targeting in mice. It is now being applied to virtually all areas of biomedicine - from basic research to the development of new therapies.

Gene targeting is often used to inactivate single genes. Such gene "knockout" experiments have elucidated the roles of numerous genes in embryonic development, adult physiology, aging and disease. To date, more than ten thousand mouse genes (approximately half of the genes in the mammalian genome) have been knocked out. Ongoing international efforts will make "knockout mice" for all genes available within the near future.

With gene targeting it is now possible to produce almost any type of DNA modification in the mouse genome, allowing scientists to establish the roles of individual genes in health and disease. Gene targeting has already produced more than five hundred different mouse models of human disorders, including cardiovascular and neuro-degenerative diseases, diabetes and cancer.


The first reports in which homologous recombination in ES cells was used to generate gene-targeted mice were published in 1989. Since then, the number of reported knockout mouse strains has risen exponentially. Gene targeting has developed into a highly versatile technology. It is now possible to introduce mutations that can be activated at specific time points, or in specific cells or organs, both during development and in the adult animal.

Almost every aspect of mammalian physiology can be studied by gene targeting. We have consequently witnessed an explosion of research activities applying the technology. Gene targeting has now been used by so many research groups and in so many contexts that it is impossible to make a brief summary of the results.

This last paragraph gets at an issue that I brought up in a post last month about some of the arguments used by opponents of animal research in the UK. Specifically, some were claiming that animal research was increasing in academia, despite the fact that industry had been able to curtain its use of animals. This implied that academics were using animal research recklessly and needlessly--a charge that is absolutely false. While the number of animal experiments performed in British academia had increased by 52% over the last ten years, this increase hadn't even kept up with the expansion of science in general in the UK (science funding had more than doubled during that period).

Regardless, this 52% increase can be almost solely attributed to the increasing use of knockout and knock-in animals (see the earlier post for details). Today's Nobel Prize announcement helps emphasize the importance of this research and further detracts from argument that such research is unnecessary or unjustifiable.

Check out Terra Sigillata for more on the Prize and how the predictions stacked up.

Jim Hu at Blogs for Industry also has an informative post about the prize.

More like this

Hey Nick, sorry I missed you in College Station. As you might expect, I've got a post up about the prize too. I had a class with Smithies when I was at Wisconsin. He's an amazing guy.

Hi Jim,

I added a link to your post, which was quite informative. I'm sure it won't be too long before I'm back down at A&M, so I'll stop by again then.