Mapping interspecific genetic architecture in host-parasite interaction system

Under a hypothesis that the host-parasite interaction system is governed by genome-for-genome interaction, we propose a genetic model that integrates genetic information from both of the host and parasite genomes. The model can be used for mapping quantitative trait loci (QTLs) conferring the interaction between host and parasite and detecting interactions among these QTLs. A one-dimensional genome scan strategy is used to map QTLs in both of the host and parasite genomes simultaneously conditioned on selected pairs of markers controlling the background genetic variation; a two-dimensional genome scan procedure is conducted to search for epistasis within the host and parasite genomes and interspecific QTL by QTL interactions between the host and parasite genomes. Permutation test is adopted to calculate empirical threshold to control the experimental-wise false positive rate of detected QTLs and QTL interactions. Monte Carlo simulations were conducted to examine the reliability and efficiency of the proposed models and methods. Simulation results illustrated that our methods could provide reasonable estimates of the parameters and adequate powers for detecting QTLs and QTL by QTL interactions.