Sex-specific and interacting QTL. (A-G) Allele effects determined at the peak marker for 7 sex-specific QTL showing a ΔLOD > 2 between sex-interactive and sex-additive LOD scores. Female effects are shown in red, males in blue. The 3 possible genotypes for each QTL are given on the ordinate, with the QTL name and Chr position below. CHCM values are shown on the y-axis. Alleles: K, C57BLKS/J; S, SM/J; B, C57BL/6J; D, DBA/2J; Z, 129S1/SvImJ; A, A/J; M, MRL/MpJ; C, C3H/HeJ; *P < .05. (H) Chcmq11 was detected in cross CByx129SI as a significant “shoulder peak” closely linked to Chcmq2 on Chr 9 with a ΔLOD (dotted purple line) > 2 between the sex-interactive (solid red line) and sex-additive (solid black line). x-axis, Chr position on Chr9 in cM. y-axis, LOD score. (I) Pairwise scans detected 2 additional QTL, Chcmq13 and Chcmq14, showing significant gene interaction (epistasis). The effects of gene interaction predicted by multiple regression are shown for the 9 possible genotypes for Chcmq14 and Chcmq13, indicated at the bottom. Complex allele-specific interactions are apparent. Alleles: A, A/J; Z, 129S1/SvImJ. y-axis, CHCM value. *P < .001 compared with AZ and ZZ Chcmq13 genotypes with heterozygosity at the Chcmq14 locus. **P < .001 vs heterozygosity for Chcmq13 with homozygosity for 129S1 alleles at Chcmq14. No other significant differences.