Genetic mapping of the virulence phenotype identified the ROP5 locus as the single major QTL.

<p>A) The parents and progeny of the genetic cross between type 2 ME49-FUDR^r and type 10 VAND-SNF^r strains were assessed for virulence in 5 outbred CD-1 mice per strain. (B) A QTL scan of the virulence phenotype generates one significant peak on the left end of chromosome XII with a LOD score of 6.95 and effect size 71%. Genome-wide LOD significance thresholds were obtained from 10,000 permutation tests, α .05 ≥ LOD 2.7. (C) A secondary scan of the virulence phenotype with the locus on chromosome XII run as an additive covariate. (D) A two-dimensional genome scan with a full model testing for interacting QTLs (top half) and an additive model testing for multiple QTLs without interaction (bottom half). Genome-wide LOD significance thresholds were obtained from 1,000 permutation tests.