Reference
The Diversity Outbred heterogeneous stock (J:DO) is a developing mouse population derived from progenitor lines of the Collaborative Cross (CC). The CC is a panel of recombinant inbred (RI) mouse strains that combines the genomes of eight genetically diverse founder strains - A/J, C57BL/6J, 129S1/SvImJ, NOD/ShiLtJ, NZO/HlLtJ, CAST/EiJ, PWK/PhJ, and WSB/EiJ - to capture nearly 90% of the known variation present in laboratory mice (Churchill et al. 2004). Animals from 160 incipient CC lines at early stages of inbreeding were used to establish the DO population, which is maintained by a randomized outbreeding strategy that avoids brother-sister matings. The DO and CC populations thus capture the same set of natural allelic variants derived from a common set of eight founder strains, with DO mice being outbred and the CC population being inbred. Each CC inbred strain represents a fixed and reproducible genotype; each DO animal is a unique, non-reproducible individual with an effectively limitless combination of segregating alleles.
CTC (2004), Churchill, G. A., et al.. The Collaborative Cross, a community resource for the genetic analysis of complex traits. Nat Genet. 36, 1133-7.