Fig. 5.

The figure is set up similarly to Fig. 4. It illustrates the impact by which two loci independently contribute to phenotype compared with a conventional QTL. Log-likelihood associated with the additive model (LOD_additive) are plotted in the top left triangle. LOD_{additive v. 1-QTL} is plotted in the bottom right triangle, and the figure demonstrates the improvement of the additive model over all possible single-QTL models. Numbers on the left and right of color scale correspond to LOD_additive and LOD_{additive v. 1-QTL}, respectively. Significance thresholds were determined by performing a 10,000 permutation test. Indicated by a circle are the maximum LOD_additive score of 11.1 and LOD_{additive v. single-QTL} score of 4.08, identifying 14.3 and 76.7 cM on mouse chromosome 1 as loci of interest. For more information, see text.