**7. Conclusions**

Despite occasional arguments to the contrary [188, 189], mice, when used correctly, are a good model of human biology and medicine [12, 190–192]. Indeed, at least 40 Nobel Prizes have been awarded for research involving mice (http:// www.animalresearch.info/en/medical-advances/nobel-prizes) [193], and their use has been vital in understanding the pathogenesis of many diseases. For true predictive medicine, we need to understand all gene-by-gene-by-environmentby-age-by-sex-by-treatment interactions [160], and animal models are the only way to do this at scale. The importance of using genetically diverse mice has often been overlooked, leading to difficulties with translation. RI families, such as the BXDs, and their expansions [130], including diallel crosses and reduced complexity crosses [194, 195], overcome this problem and are a vital step towards accurate, individualized, predictive medicine.
