Experiment
Newly created NOD.C3H (donor strain = C3H/HeJ-diabetes resistant, recipient strain = NOD/Lt-diabetes susceptible) recombinant congenic (RC) strains allowed finer mapping of loci linked to diabetes, Idd6 and Idd19, on mouse Chromosome 6. In addition, a novel locus, Idd20, was detected on proximal chromosome 6. NOD.C3H RC strains were derived from successive backcrossing of (NOD/Lt x C3H/HeJ)F1 females to NOD/Lt males. Phenotyping and genotyping of several NOD.C3H strains localized Idd6 (susceptibility locus) to a 3.9 cM interval between D6Mit57 and D6Mit304 (approximately 71.1 cM - 75 cM) and localized Idd19 (resistance locus) to an 11.3 cM interval between D6Mit288 and D6Mit289 (approximately 51 cM - 62.3 cM). Possible candidate genes in the region of Idd19 are Tnfrsf7, Tnfrsf1a, and Hrh1. Idd20 (susceptibility locus) maps to a 1.5 cM interval between D6Mit100 and D6Mit31 (approximately 37 cM - 38.5 cM). Idd6, Idd19, and Idd20 appear to interact epistatically.
Analysis Tools