The main reasons we use mice are that their are small, we can screen lots of them and that they have a relative short life spam (a normal lab mouse lives usually around 2 years). It means that they get old quicker than other animals and that we can screen as many mice as we can in a shorter period of time. At the same time, the genes of the mouse are very very similar to the genes of a human so whatever we find can be potentially be looked in old people (and that is called “translation”).
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