Genome‐wide mapping to identify quantitative trait loci (QTLs) for social behaviors measured in the direct (DSI) and 3‐chamber (3C) social interaction tasks. (A), DSI partner sniffing is not associated with any suggestive or significant loci. (B), DSI ultrasonic vocalization (USV) count is associated with a significant QTL on Chr 18 (upper line) and 3 suggestive loci on Chr 1, 14 and 19 (lower line). (C), 3C social approach sniff preference is associated with 3 suggestive loci on Chr 5, 10 and 19. Mapping color corresponds to the color of the primary factor containing each trait that was identified using PCA in Table 2. (D), Summary of QTL locations, peak LRS scores and locations, additive effect sizes and genotypes, gene numbers and number of genes with sequence variants, and candidate quantitative trait genes (QTGs). Candidate QTGs are listed in order of location on each on each Chr and were selected based on evidence of (1) QTLMiner ratings based on gene expression in brain, cis‐regulation and presence of nonsynonymous SNPs or Indels, (2) significant correlation between trait means and transcript expression in the hippocampus, hypothalamus or amygdala (P < .01, expression datasets in GN, bolded) or (3) involvement in human neurological disorders or key phenotypes related to social behavior or communication (starred). CIM controlling for the social approach peak on Chr 10 revealed an additional suggestive locus on Chr 4 (CIM‐4; data shown in Figure S4). Significant LRS scores are bolded and starred. Superscripts indicate that the loci on Chr 10 are linked (Spearman ρ .795) and are considered a single QTL. Chr, chromosome; CIM, composite interval mapping; Indels, insertions/deletions; LRS, likelihood ratio statistic; nsSNPs, nonsynonymous single nucleotide polymorphisms; SA, social approach session; QTGs, quantitative trait genes. &Drop‐support intervals were 0.5‐LOD for loci with LOD scores below 3.0 and 1.0‐LOD for loci with LOD scores above 3.0. CIM loci were required to have LOD scores of 2.50 or greater to be listed. Note: The 4 genes in QTL 19 are adjacent to the locus on either side; there are no genes within the locus