>guarantees you won't things that can't be learned from the single, genetically uniform mouse type that is used.

This is a misrepresentation of the state of mouse biology research.

We use many different strains of inbred mice (check out the JAX Labs list of available inbreds)[1]. Inbreeding reduces the genetic variability of our mice, allowing us to control more of the variation in an experiment. This allows us to perform pilot studies with smaller samples sizes while still reaching sufficient statistical power. This is important -- mouse biology is expensive, and we try to discover as much as possible with limited funding.

If a result merits generalization to multiple backgrounds, it is often tested in multiple inbred strains and an "outbred" strain that is genetically diverse.

[1] - https://www.jax.org/jax-mice-and-services/find-and-order-jax...