Nobel Prize awarded for revolutionary gene-targeting method in mice

Last week the Nobel Prize for Medicine was jointly awarded to three scientists for their pioneering work on embryonic stem cells (ES cells) in mice. The trio, comprising US scientists Mario R. Capecchi and Oliver Smithies, and UK scientist Martin J. Evans, developed a technique known as 'gene targeting', which has since helped scientists worldwide to establish the roles that a whole host of individual genes play in health and disease.

The Nobel committee said: 'their discoveries led to the creation of an immensely powerful technology...now being applied to virtually all areas of biomedicine - from basic research to the development of new therapies.'

Each scientist made their own unique contribution to this revolutionary technology. Sir Evans, Professor of Mammalian Genetics at Cardiff University, discovered that embryonic stem cells  from mice had the power to develop into any tissues of the body, and that harmless 'retroviruses' could be used to insert new gene sequences into these cells. By injecting these genetically modified ES cells into a developing mouse embryo inside a female mouse, and then breeding the resulting offspring with a normal mouse, he found that a new genetically modified mouse could be created.

The ability to induce targeted gene changes within the mouse genome- known as a gene 'knockout' - arose from independent work by Capecchi and Smithies. By using this technology to introduce specific genetic modifications into mouse ES cells they were able to create mouse models of human genetic disorders, helping scientists worldwide to develop a better understanding of human health and disease.

Goran Hansson, a member of the Nobel committee, told the Independent newspaper that targeting genes had transformed the understanding of human physiology and medicine. 'It is difficult to imagine contemporary medical research without the use of gene-targeted models', he added. 'The ability to generate predictable designer mutations in mouse genes has led to penetrating new insights into development, immunology, neurobiology, physiology and metabolism'.

The Nobel committee believe that the major benefits to human health gained from knockout mouse technology will not end here. 'Gene targeting has already produced more than five hundred different mouse models of human disorders, including cardiovascular and neuro-degenerative diseases, diabetes and cancer', they said. 'Its impact on the understanding of gene function and its benefits to mankind will continue to increase over many years to come'.