1939 International Committee on Standardized Nomenclature for Mice begins, bringing order to the naming of mice and their genes. Harwell becomes Europe's hotbed of mouse genetics. Researchers at Oak Ridge National Laboratory in the United States also do radiation studies. The mutant mice lead to major advances in mouse genetics. A fire destroys most of The Jackson Lab and its mice.
Researchers rally to rebuild stocks.
This opens new areas of immunological research and earns Snell a Nobel Prize. The informal Mouse News Letter begins its 40 years of publication under that name. At its peak, some 60 labs contribute to it. 1950 Obese mouse is discovered at The Jackson Lab. The first animal model for obesity, the mouse later proves to have a key mutation in the leptin gene.