Libraries of mice are established using ENU-injected male mice, producing offspring which are heterozygous for random ENU-induced mutations in the genome. Pedigrees can be screened for phenotypes of interest, however, the random nature of ENU means that small libraries will not always produce a large amount of phenotypic variation required. They have the resources to produce large libraries giving researchers a greater probability of accessing their phenotype of interest, without carrying the costs and risks of production themselves.

Mice can be screened in the heterozygous or homozygous state, depending on the phenotype/trait/disease/disorder of interest. Once a phenotype of interest has been identified, further phenotyping can be performed if required, either by us or the researcher is free to obtain the strain and perform their own investigations.