Tracking down the genes behind non-Mendelian traits can be complicated given the sheer numbers of genes involved. Now Eric Lander of the Whitehead Institute for Biomedical Research, Cambridge, Mass., Joseph Nadeau of Case Western Reserve University, Cleveland, Ohio, and colleagues have created a resource that could make the job easier.1
The researchers bred a series of 22 C57BL/6J mouse strains, each containing a single chromosome or mitochondrial DNA from an A/J donor. This chromosomal substitution strain (CSS) collection allows researchers to probe each chromosome individually. "It's simply a matter of doing the phenotyping to see if the given strain differs from the host strain, implying then that there's at least one gene on that substituted chromosome that affects the trait of interest," says Nadeau.
To illustrate the power of this approach, the researchers probed such traits as diet-induced obesity, anxiety, and serum cholesterol levels. Whereas earlier studies found only a ...
