Position of IRF3 and overlap of QTLs in mouse, human, cattle and sheep. QTL positions are indicated by bold blue lines. Green boxes indicate the localisation of syntenic blocks conserved between species. Inversions of the gene order are indicated by red arrows. Markers located on the boundaries of the QTLs in mouse (susceptibility to Mycobaterium tuberculosis), human (Coxsackie virus resistance), cattle (susceptibility to clinical mastitis) and sheep (Nematodirus egg count) or the blocks of conserved synteny are indicated in blue. Under the assumption that the indicated QTLs are caused by the same loci, the significant region can be narrowed to two segments with a combined length of less than 7 Mb (brown line in syntenic blocks). Immunologically relevant genes located in these regions are listed in additional file 4: Immunologically relevant genes in regions of conserved synteny surrounding the TLR1 family cluster, MyD88 and IRF3.