Early social rearing, the V1A arginine vasopressin receptor genotype, and autistic traits in chimpanzees

Abstract

Previous studies found associations between autism‐related phenotypes and both rearing and V1A arginine vasopressin receptor (AVPR1A) genotypes. We tested whether these exposures as well as their interaction were associated with autism‐related phenotypes in 121 laboratory‐housed chimpanzees. We used expert‐derived weights to obtain autism scores from ratings on the 43‐item Chimpanzee Personality Questionnaire; higher scores indicated more autistic‐like traits. The first model included fixed effects for sex, age, and rearing, and a random effect that addressed the relatedness of subjects. The second model was the same except that it also included the rearing × AVPR1A genotype interaction as a fixed effect. Both models indicated that the phenotype was moderately heritable and that chimpanzees reared by their mothers had lower scores on the scale. The effect of genotype in both models indicated that chimpanzees with an indel deletion had higher scores on the scale, although the credible interval included zero. Moreover, the rearing × genotype interaction in the second model indicated that chimpanzees who possessed the non‐deletion genotype and who were reared by their mother were at even greater risk. The credible interval for this effect did not include zero, but fit statistics indicated that the model without the interaction was marginally better, and the interaction was in the opposite direction than we expected based on previous work. These findings highlight the importance of rearing effects in the typical social development of our closet‐living nonhuman relative. Lay summary We tested whether, in chimpanzees, scores on a scale comprising traits that resembled aspects of autism were related to a gene associated with autism in prior research and/or early rearing. Human‐reared chimpanzees had higher scores (indicating more autistic‐like traits). Chimpanzees that possessed the gene also had higher scores, but we could not exclude the possibility that there was no effect of genotype. These findings suggest that we can measure autism‐like characteristics in chimpanzees, and so study it in this species.

Characterizing the personality and gray matter volume of chimpanzees that exhibit autism-related socio-communicative phenotypes

“…Nonhuman animals are important models for studies on the genomic and neural systems that contribute to behaviors that are used as model phenotypes of ASD (Bauman & Schumann, 2018 ; Silverman et al, 2022 ). In nearly all primate species used as animal models for ASD, different dimensions of social behavior or personality have been the behavioral phenotypes of interest (Yirmiya et al, 2006 ; Mahovetz, Young & Hopkins, 2016 ; Proctor, Calcutt, Burke & de Waal, 2016 ; Wilson et al, 2017 ; Parker et al, 2018 ; Weiss, Wilson & Hopkins, 2021 ; Gunter et al, 2022 ). By contrast, however, there are surprisingly few studies that have focused on overt measures of social cognition, including joint attention (Hopkins et al, 2014a).…”

Genetic determinants of individual variation in the superior temporal sulcus of chimpanzees (Pan troglodytes)

“…Polymorphisms in AVPR1A are also associated with a composite score reflecting ASD phenotypes (Weiss et al 2021) as well as social cognition measures linked to ASD, notably receptive joint attention (RJA) . Previous studies have also found that both humans and chimpanzees with poor joint attention skills differ in gray matter volume of the posterior, but not anterior, portion of the superior temporal gyrus (Hopkins, Misiura, et al 2014;Mundy 2018).…”