One strain can see farther than normal into the red part of the spectrum, thanks to a human photopigment gene, and another manufactures human growth hormone. Mice are particularly valuable in identifying human genes, because genome organization corresponds so closely between the two species. Mammalian genomes are all derived from the same original mammalian chromosome set. Take that set, cut it into about 150 pieces, and shuffle the pieces. One way produces a human, another way, a mouse.
Databases match human and mouse genes.
Many anatomical structures are similar between the species, too. Mouse variants arise in several ways. It appeared in a stock at the Jackson Laboratory in 1990. Radiation or chemicals also are used to induce mutations. In 1993, the Jackson Laboratory started the Mouse Mutant Resource to distribute induced, transgenic, and knockout mice from research labs.