The Collaborative Cross (CC) is currently being generated as a community resource for more sensitive and refined mapping of QTLs. The goal is to breed a large population of recombinant inbred strains starting from eight founder strains. The eight founder strains were selected to capture a large portion of the genetic variation in the mouse genome. In fact, the genetic variation represented in the CC will be twice the genetic variation present in the human population (reviewed in Valdar et al. 2006) . The three sites where the resource is being generated reported the present status of their breeding colonies; the final goal is to generate a total of 700 lines (Chesler et al. 2008; Iraqi et al. 2008; Morahan et al. 2008a) . Grant Morahan gave an update on the ''Southern Cross'' being established in Perth, Australia. An inbreeding depression was observed at generations 7-9. At present, about 200 strains have been bred beyond generation 10. The first 40 strains are expected to be inbred by the end of the year. David Threadgill reported the status of the breeding colony at the University of North Carolina, Chapel Hill, NC, USA. About 300 lines are currently breeding at UNC. The first 50 recombinant inbred lines will be available by the end of this year and 200 lines by the end of 2011. To speed up the inbreeding process, markerassisted breeding will be used to create homozygous lines beyond generation 12. Genome analysis demonstrated that all parental genomes are well represented in the advanced generations. The first phenotyping analysis showed a large variation in body weight, exercise propensity, and susceptibility to pathogens. Richard Mott described the genome structure of a smaller CC colony, funded by the Wellcome Trust, which was developed by Fuad Iraqi and is presently housed in Tel Aviv, Israel. A first phenotyping analysis for the QTLs that affect recombination frequencies was performed. A full-genome sequencing project to complete the parental strains with high coverage is underway at the Sanger Institute.