the past decade (Fig. 1b and Supplementary Data 2). On average 1.5 × 106 mRNA, 1.7 × 104 proteomic and 6.8 × 103 metabolomic assays are available per strain (Fig. 1b). Most phenotypes vary markedly across strains within the family. For example, effects of high-fat and low-fat diets on adult body weight vary substantially across genotypes (Fig. 1c). Similarly mRNA and protein expression of, for example, Bckdhb and many other mRNA, proteins, and metabolites vary greatly (Fig. 1d)10. The online availability of well-organized classic and molecular traits from the BXD family (see www.genenetwork.org) provides the foundation for multiscalar phenome scans of any putatively functional sequence variant.
