Imagine a new drug for type 2 diabetes. The researchers developing the drug would have used a mouse model of type 2 diabetes — in other words, a mouse that has the same kind of genetic variations as a patient with the disease. Before the drug goes to clinical trials to be tested on patients, the U.S. Food and Drug Administration dictates that it first be tested in mice. The trouble is, unlike the human patient population, the mice used in testing are all very genetically uniform, a cross between two standard inbred strains. That’s basically like testing the drug on just two people. So it should come as no surprise that the drug might not work in every patient.
But there’s a new approach on the horizon. Jackson Laboratory scientists and their international collaborators devised the Collaborative Cross (CC): a mouse population established with eight different founder strains, including standard inbred strains but also some wild-type mice. Crossing these animals shuffles the genetic deck to yield populations of mice with greater genetic diversity than is present in the entire human race.
Testing a drug on a collection of CC mice yields extremely useful information. Scientists can identify which mice the drug works well in, which mice it doesn’t work at all in, and which mice experience a toxic reaction to the drug. And thanks to genome sequencing, the scientists can identify exactly which genes are responsible for these reactions. So a patient could take a genetic test before using the drug to ensure that it would be both safe and effective.