Genetics of Human Social Behavior Richard P. Ebstein, Salomon Israel, Soo Hong Chew, Songfa Zhong, Ariel Knafo  Neuron  Volume 65, Issue 6, Pages 831-844 (March 2010) DOI: 10.1016/j.neuron.2010.02.020 Copyright © 2010 Elsevier Inc. Terms and Conditions

Figure 1 Pathway to Gene Discovery for Social Behaviors In the search for social genes, the definition of phenotype is crucial. Social behaviors can be characterized by pencil and paper questionnaires, laboratory models, and natural experiments. Once the phenotype is defined, the MZ-DZ method is used to estimate the overall contribution of heredity (A: additive genetic effects) and environment (C: shared; E: nonshared). Animal models, informed hypotheses, and good hunches based on neurochemical and neuropharmacological experiments provide models of specific neurotransmitter systems that mold specific social behaviors and ipso facto suggest candidate genes. Neuron 2010 65, 831-844DOI: (10.1016/j.neuron.2010.02.020) Copyright © 2010 Elsevier Inc. Terms and Conditions

Figure 2 MZ-DZ Correlations for Social Phenotypes Comparison of MZ and DZ correlations along a broad swath of social phenotypes. A short description and reference to all the phenotypes listed is provided in Table S2. Neuron 2010 65, 831-844DOI: (10.1016/j.neuron.2010.02.020) Copyright © 2010 Elsevier Inc. Terms and Conditions

Figure 3 Heritability of Social Behavioral Phenotypes The relative influences of genetic effects (both additive and dominant), the shared environment, and the unshared or unique environment (which also includes measurement error) in contributing to social phenotypes. Phenotypes are listed in order of estimated genetic effects, with descriptions and references provided in Table S2. Neuron 2010 65, 831-844DOI: (10.1016/j.neuron.2010.02.020) Copyright © 2010 Elsevier Inc. Terms and Conditions

Figure 4 Vasopressin/Oxytocin Schematic, and Genetic Variation (SNPs) across the OXTR and AVPR1a Genes (A) The nonapeptides OT and AVP differ in two amino acids. (B) AVPR1a has two exons and three repeat regions: two in the promoter region (RS1 and RS3) and one intronic repeat. (C) The OXTR contains three introns and four exons. Several dozen SNPs have been identified within the gene, and the figure shows only tagging SNPs obtained from the HapMap database and Haploview program. A tagging SNP is a representative SNP in a region of the genome with high linkage disequilibrium (the nonrandom association of alleles at two or more loci). It is possible—and also cost-effective—to capture most of the genetic variation without genotyping every SNP in a chromosomal region. Neuron 2010 65, 831-844DOI: (10.1016/j.neuron.2010.02.020) Copyright © 2010 Elsevier Inc. Terms and Conditions

Figure 5 Games in Play in Experimental Economics The dictator (Forsythe et al., 1994; Kahneman et al., 1986), ultimatum (Guth et al., 1982), and trust (Berg et al., 1995) games. Games have been widely studied in the emerging field of neuroeconomics (Fehr and Fischbacher, 2003). These games illustrate fundamental concepts of dyadic social interactions including fairness, altruism, and preferences for equity. Neuron 2010 65, 831-844DOI: (10.1016/j.neuron.2010.02.020) Copyright © 2010 Elsevier Inc. Terms and Conditions