Illustration of how transgenic mice are produced.
Genes responsible for particular traits or disease susceptibility are
chosen and extracted. Next they are injected into fertilized mouse eggs.
Embryos are implanted in the uterus of a surrogate mother. The selected
genes will be expressed by some of the offspring.
Since the first gene transfers into mice were successfully executed in
1980, transgenic mice have allowed researchers to observe experimentally
what happens to an entire organism during the progression of a disease.
Transgenic mice have become models for studying human diseases and their