Fine-scale analysis of parasite resistance genes in the red flour beetle, Tribolium castaneum

Parasite infection impacts population dynamics through effects on fitness and fecundity of the individual host. In addition to the known roles of environmental factors, host susceptibility to parasites has a genetic basis that has not been well characterized. We previously mapped quantitative trait loci (QTL) for susceptibility to rat tapeworm (Hymenolepis diminuta) infection in Tribolium castaneum using dominant AFLP markers, but the resistance genes were not identified. In the current study, we refined the QTL locations and increased the marker density in the QTL regions using new microsatellite markers, sequence-tagged site markers (STS), and single-strand conformational polymorphism markers (SSCP). Resistance QTL in three linkage groups, (LG3, LG6 and LG8), were each mapped to intervals less than 1.0 cM between two codominant markers. The effects of 21 genes in the three QTL regions were investigated by using quantitative RT-PCR analysis, and transcription profiles were obtained fr...