page_title: History of model organisms
section_title: Mice
hierarchical_section_title: History of model organisms / Modern model organisms / Mice
caption_attribution_description: English: Common house mouse (Mus musculus), wild type. Edited to change the background color.
context_page_description: The history of model organisms began with the idea that certain organisms can be studied and used to gain knowledge of other organisms or as a control for other organisms of the same species. Model organisms offer standards that serve as the authorized basis for comparison of other organisms. Model organisms are made standard by limiting genetic variance, creating, hopefully, this broad applicability to other organisms.
  The idea of the model organism first took root in the middle of the 19th century with the work of men like Charles Darwin and Gregor Mendel and their respective work on natural selection and the genetics of heredity. These early works in finding standards to compare organisms against continued into the 20th century as the first model organisms were brought into laboratories. Beginning in the early 1900s Drosophila entered the research laboratories and opened up the doors for other model organisms like Tobacco mosaic virus, E. coli, C57BL/6, etc. These organisms have led to many advances in the past century.
context_section_description: Both the community of insects and the viruses were a good start to the history of model organisms, but there are yet still more players involved.  At the turn of the century much biomedical research was being done using animals and especially mammalian bodies to further biologists’ understanding of life processes.  It was around this time that American humane societies became very involved with preserving the rights of animal and for the first time were beginning to gain public support for this endeavor.   At this same time American biology was also going through its own internal reforms.  From 1900 to 1910 thirty medical schools were forced to close.  During this time of unrest a man named Clarence Cook Little, through a series of luckily timed events, became a researcher at Harvard Medical School and worked on mouse cancers.  He began developing large, mutant strain, colonies of mice.  Under the charge of Dr. William Castle, Little helped to expand the animal breeding habits in the Bussey laboratory at Harvard.  Due to freedom in the way Castle was allowed to run the laboratory and his financial backing by the University they were able to create an extensive program in mammalian genetics.
  The mice turned out to be an almost perfect solution for test subjects for mammalian genetic research.  The fact that they had been bred by ‘rat fanciers’ for hundreds of years allowed for diverse populations of an animal while the public held far less sentiment for these rodents than they did for dogs and cats.  Because of social allowance, Little was able to take new ideas of ‘pure genetic strains’ merging from plant genetics as well as work with Drosophila and run with them.  The idea of inbreeding to achieve this goal of a ‘pure strain’ in mice was one that may have created a negative response to the fertility of the mice thus discontinuing the strain.  Little achieved his goal of a genetically pure strain of mice by 1911 and published his finding shortly thereafter.
  He would continue his work with these mice and used his research to demonstrate that inbreeding is an effective way of eliminate variation and served to preserve unique genetic variants.   Around this time as well there was much work being done with these mice and cancer and tumor research.
  Throughout the 1920s’ work continued with these mice as model organisms for research into tumors and genetics.  It was during the great depression that this field of study would take its biggest blow.  With the economy at rock bottom labs were forced into selling many of their mice just to keep from shutting down.  This necessity for funds all but stopped the continuation of these strains of mice.  The transition for these laboratories to exporters of massive quantities of mice was one that was rather easily made if there were adequate facilities for their production on site.  Eventually in the mid-1930s the market would return and genetics laboratories around the country resumed regular funding and thus continued in the areas of research they had started before the depression.  As research into continued, so did the production of mice in places like Jackson Laboratory.  Facilities like these were able to produce mice for research facilities around the world.  These mice were bred with Mendelian breeding technique of which Little had implemented as standard practice around 1911.  This meant that the mice being experimented on were not only the same within the laboratory, but in different laboratories around the world.
  The mouse has remained important as molecular genetics and genomics have progressed; sequencing of a reference mouse genome was completed in 2002.
  More broadly, comparative genomics has advanced our understanding and reinforced the importance of model organisms, especially ones with relatively small and nonrepetitive genomes.
caption: House mouse, the most important mammal model organism
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