Experiment
126 C57BL/6Ola x (NZW/Ola x B6.Yaa)F1 male backcross animals were typed for 95 polymorphic markers at an average density of 20 cM to identify QTLs associated with Y-linked autoimmune disorder phenotypes such as glomerulonephritis, IgG anti-DNA autoantibody production, and retroviral gp70 antigen production. NZW/Ola is susceptible to lupus-like autoimmune syndrome while C57BL/6Ola is resistant. The B6.Yaa congenic, while carrying the lupus susceptibility Yaa gene, is resistant to disease, but male hybrid animals from a (NZW x B6.Yaa)F1 cross develop severe autoimmune disease. (The B6.Yaa strain was constructed by Izui et al in 1988 and carries the Y chromosome from susceptible strain BXSB/MpJ on a C57BL/6 background.) Yaail (Yaa interacting locus), a QTL associated with glomerulonephritis and IgG anti-DNA autoantibody production was detected on mouse chromosome 7 from 3.4 cM - 23 cM with a peak LOD score of 4.4 near Cd22. Yaa1, a locus associated with retroviral gp70 antigen production, was detected on mouse chromosome 13 from 31 cM - 40 cM, with a peak LOD score of 12.8 near D13Mit250. Yaa1 appears to interact with Yaail to increase gp70 IC formation. Modifying loci were detected on mouse chromosome 17 from 4.1 cM - 23 cM for IgG anti-DNA antibody production (Myaa1 (modifier of Yaa-related QTL), maximum LOD = 8.1 at D17Mit164 in interaction with Yaa1) and 4.1 cM - 42 cM for glomerulonephritis (Myaa2, maximum LOD = 6.9 at D17Mit36 in interaction with Yaail).
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