Genetically and genomically, the mouse and the human are very similar, with many of the disease-related genes are nearly identical. Further, the early development of inbred lines, the mouse provides a robust tool to identify the genetic basis of both normal and disease traits.

Core elements of the mouse immune system correlate with those in humans, permitting testing the efficacy of vaccines and immunotherapies for infectious diseases.

Dear Shantanu Tamuly

This is an old head to head comparison

Article Comparison of vaccination of mice and rats with Haemophilus ...

The mouse is about 30 gr and eats per day about 3g pellets. A rat is about 300 g and is much more expensive to feed. The greater the animal is the more unpleasant it is to euthanize the animal. Both mice and rats are very good models for the human being, the learn well and are clever and fun.