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

Abstract

The superior temporal sulcus (STS) is a conserved fold that divides the middle and superior temporal gyri. In humans, there is considerable variation in the shape, folding pattern, lateralization, and depth of the STS that have been reported to be associated with social cognition and linguistic functions. We examined the role that genetic factors play on individual variation in STS morphology in chimpanzees. The surface area and depth of the STS were quantified in sample of 292 captive chimpanzees comprised of two genetically isolated population of individuals. The chimpanzees had been previously genotyped for AVPR1A and KIAA0319, two genes that play a role in social cognition and communication in humans. Single nucleotide polymorphisms in the KIAA0319 and AVPR1A genes were associated with average depth as well as asymmetries in the STS. By contrast, we found no significant effects of these KIA0319 and AVPR1A polymorphism on surface area and depth measures for the central sulcus. The overall findings indicate that genetic factors account for a small to moderate amount of variation in STS morphology in chimpanzees. These findings are discussed in the context of the role of the STS in social cognition and language in humans and their potential evolutionary origins.

Neuroimaging genomics as a window into the evolution of human sulcal organization

“…Interestingly, this enrichment was detected in the right hemisphere, which might highlight the prominent rightward asymmetries in the central regions of the superior temporal sulcus, with particular differences in depth across hemispheres, which are less pronounced in chimpanzees ( Leroy et al. 2015 ; Hopkins et al. 2023 ).…”

Neuroimaging genomics as a window into the evolution of human sulcal organization

“…Additionally, we identified significant heritability enrichment in foetal brain HGEs for the width of the superior temporal sulcus, which is known for its involvement in social perception and cognition, and deemed to have a key role in the convergence of spoken and written language (Deen et al 2015; Wilson et al 2018). Interestingly, this enrichment was detected in the right hemisphere, which might highlight the prominent rightward asymmetries in the central regions of the superior temporal sulcus, with particular differences in depth across hemispheres, which are less pronounced in chimpanzees (Leroy et al 2015; Hopkins et al 2023). Altogether, the enrichment signals in foetal brain HGEs for the entirety of the central sulcus, the right parieto-occipital sulcus, and the superior temporal sulcus may indicate the involvement of human-gained gene regulatory elements in the evolution of human hand dexterity, social cognition, and speech.…”

“…Interestingly, this enrichment was detected in the right hemisphere, which might highlight the prominent rightward asymmetries in the central regions of the superior temporal sulcus, with particular differences in depth across hemispheres, which are less pronounced in chimpanzees (Leroy et al 2015;Hopkins et al 2023). Altogether, the enrichment signals in foetal brain HGEs for the entirety of the central sulcus, the right parieto-occipital sulcus, and the superior temporal sulcus may indicate the involvement of human-gained gene regulatory elements in the evolution of human hand dexterity, social cognition, and speech.…”