Genetic characterization of the congenic strains used. (Black lines) NOD genome; (red regions) location of the B10- or B6-derived congenic segments (with the exception of the B10.Idd3 strain for which the congenic interval is NOD-derived and hence represented by a black line). (Blue text) Key microsatellites that define the boundaries of the congenic segments and/or the location of the Idd loci; (red vertical bars) position of each Idd locus. The locations of known candidate genes are shown. Because of space constraints, the candidates Cflar, Casp8, Cd28, andCd152 (Ctla4), which map to the Idd5.1locus, and Cd137, which maps to the Idd9.3 locus, are not shown. All distances are given in centimorgans.