I know this doesn't answer your question as much as it introduces more questions, but I recall there being a propensity to use mice for these studies because gene expression based on lineage is more reliable in mice, the effects of metabolic modification are easier to study in mice, and a lot of existing studies are done on mice so it is easier to advance research. I may have read this in a biologists AMA on Reddit, so take it with a grain of salt. I also very much agree that study reproducibility is a major problem. Everyone wants to do the original research, and few want to validate existing work.
