In animal research we often refer to genotype and phenotype. Genotype refers to the set of genes the animals the animals carry (what they are capable of expressing) and phenotype refers to the physical/clinical expression/presentation/characteristics of the animal or disease state. My guys were all "wild type" meaning they're just "normal" standard mice and we induced the "obese phenotype" (obese disease state with the associated characteristics and physical presentation associated with the disease) with the two high fat diets. 60% had a greater impact on inducing these changes compared to the control group than the 40% group.