[robwwilliams]

Not sure why you think weight is such a key variable. Might make sense if you had focused in bone mineral density—although mice have been extremely useful to study osteoblast and osteoclast biology.

Mice gave us a very solid understanding of cancer genetics. Cancer was initially thought of as an almost purely environmental disease. Thanks to “in mice” we learned that genetic susceptibility is a major factor.

Transplantation biology and immunology have profited enormously from mouse models—-and more “recently” everything from monoclonal antibodies to CAR-T cells.

And when you say “brain” who could been a dozen different things. I can assure you that mouse models are highly useful and translationally relevant to many neurological, behavioral, developmental, and physiological studies of the mammalian brain.

[cyberax]

> Not sure why you think weight is such a key variable.

I worked in cancer research-adjacent area (on computational biology). The problem with mice was that cancers in mice necessarily contain fewer cells than human cancers.

So a lot of treatments can simply clear these cancers completely, without giving them a chance to evolve resistance. Yes, you can try to compensate for that, but it just is not reliable.

In addition, mice are notoriously naturally susceptible to cancer. So their cancers, counter-intuitively, are often less evolved as a result.

> And when you say “brain” who could been a dozen different things.

I basically mean "degenerative brain diseases", very much including aging.