Experiment
The authors had previously identified two potentially overlapping QTLs Eae44 and Eae7 on mouse Chromosome 11 (see J:49054). The authors used composite interval mapping (CIM) which combines multiple regression and interval mapping to detect linked QTL anddefine more precisely the locations.
Composite interval mapping analysis was performed with the results from 681 (SJL/J x B10.S/DvTe)F2 mice (J:49054, J:53193). CIM allowed the authors to resolve Eae44 into two distinct QTLs. The first Eae44a, resides between D11Mit72 and D11Mit294 and is associated with disease severity. Lif is a possible candidate gene in this region though no sequence polymorphism was found in the Lif gene between the two strains.
The second QTL, Eae44b, is located between D11Mit307 and D11Mit140 and was associated with the duration of the disease. Il12b is a possible candidate gene in this region though no sequence polymorphism was found in the IL12b gene between these two strains.
CIM analysis also reduced the interval encodingthe Eae7 gene to a 8 cM region between D11Mit194 and D11Mit285. No sequence polymorphisms between the strains were found in Nos2, Scya3, Scya4, Scya5, Scya6, Scya7, Scya9, Scya10 and Scya11 genes, all of which map to the Eae7 interval. However, the Scya1,Scya2 and Scya12 genes which map in the Eae7 interval show polymorphisms between the two strains. Additionally, the EAE-resistant strains BALB/cJ and B10.S/DvTe, possess the same alleles for all three genes. Further studies are needed to clarify the roleof these allelic differences.
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