why do scientists often perfom experiments on mice ? (to find medicines for humans.)?

[JROXZ]

Research is done on mice to see what the results are or maybe on a lower form of the mammalian organism before moving up to higher organisms like cats, dogs, rhesus monkeys... etc then finally humans.

Drugs are tested in this way from lower to higher to rule out as many if not all the antagonistic effects before providing the therapy or treatment to humans.

We can also, in the reverse, seek a gene (sequence of DNA that codes for a certain trait or protein) from a human and implant it in mice to see what its effects may be. Thereby, experimenting with therapies and moving up the mammalian ladder once again.

[dark humour]

why do scientists often perfom experiments on mice ?
do we have somthing like the same thing ?
and also what is a gene?