Dataset Information

Primate brain architecture and selection in relation to sex.

ABSTRACT:

Background

Social and competitive demands often differ between the sexes in mammals. These differing demands should be expected to produce variation in the relative sizes of various brain structures. Sexual selection on males can be predicted to influence brain components handling sensory-motor skills that are important for physical competition or neural pathways involving aggression. Conversely, because female fitness is more closely linked to ecological factors and social interactions that enable better acquisition of resources, social selection on females should select for brain components important for navigating social networks. Sexual and social selection acting on one sex could produce sexual dimorphism in brain structures, which would result in larger species averages for those same brain structures. Alternatively, sex-specific selection pressures could produce correlated effects in the other sex, resulting in larger brain structures for both males and females of a species. Data are presently unavailable for the sex-specific sizes of brain structures for anthropoid primates, but under either scenario, the effects of sexual and social selection should leave a detectable signal in average sizes of brain structures for different species.

Results

The degree of male intra-sexual selection was positively correlated with several structures involved in autonomic functions and sensory-motor skills, and in pathways relating to aggression and aggression control. The degree of male intra-sexual selection was not correlated with relative neocortex size, which instead was significantly positively correlated with female social group size, but negatively correlated with male group size.

Conclusion

Sexual selection on males and social selection on females have exerted different effects on primate brain architecture. Species with a higher degree of male intra-sexual selection carry a neural signature of an evolutionary history centered on physical conflicts, but no traces of increased demands on sociocognitive tasks. Conversely, female sociality is indicated to have driven the evolution of socio-cognitive skills. Primate brain architecture is therefore likely to be a product of ecological and species-specific social factors as well as different sex-specific selection pressures. Our results also highlight the need for acquisition and analysis of sex-specific brain components in mammals.

SUBMITTER: Lindenfors P

PROVIDER: S-EPMC1885794 | biostudies-literature | 2007 May

REPOSITORIES: biostudies-literature

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Publications

Primate brain architecture and selection in relation to sex.

Lindenfors Patrik P Nunn Charles L CL Barton Robert A RA

BMC biology 20070510

<h4>Background</h4>Social and competitive demands often differ between the sexes in mammals. These differing demands should be expected to produce variation in the relative sizes of various brain structures. Sexual selection on males can be predicted to influence brain components handling sensory-motor skills that are important for physical competition or neural pathways involving aggression. Conversely, because female fitness is more closely linked to ecological factors and social interactions ...[more]

PMID: 17493264

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Project description:Genome-wide transcriptional profiling allows characterization of the molecular underpinnings of neocortical organization, including cortical areal specialization, laminar cell type diversity and functional anatomy. Microarray analysis of individual cortical layers across sensorimotor and association cortices in rhesus macaque demonstrated robust and specific laminar and areal molecular signatures driven by differential expression of genes associated with specialized neuronal function. Gene expression corresponding with laminar architecture was generally similar across cortical areas, although genes with robust areal patterning were often highly laminar as well, and these patterns were more highly conserved between macaque and human as compared to mouse. Layer 4 of primate primary visual cortex displayed a distinct molecular signature compared to other cortical regions, a specialization not observed in mouse. Overall, transcriptome-based relationships were strongest between proximal layers in a cortical area, and between neighboring areas along the rostrocaudal axis, reflecting in vivo cortical spatial topography and therefore a developmental imprint. Tissue from male and female monkeys (n = 2-3 animals/gender) was collected from anterior cingulate gyrus (ACG), layers 2, 3, 5, 6; orbitofrontal cortex (OFC), layers 2, 3, 5, 6; dorsolateral prefrontal cortex (DLPFC), layers 2-6; primary motor cortex (M1), layers 2, 3, 5, 6; primary somatosensory cortex (S1), layers 2-6; primary auditory cortex (A1), layers 2-6; primary visual cortex (V1), layers 2-6 including 4A, 4B, 4Calpha (4Ca), 4Cbeta (4Cb); secondary visual cortex (V2), layers 2-6; middle temporal area (MT), layers 2-6; temporal area (TE), layers 2-6; hippocampus, CA1, CA2, CA3, dentate gyrus (DG); and dorsal lateral geniculate nucleus (LGN), magnocellular, parvocellular and koniocellular divisions. Due to the limited number of samples that could be amplified concurrently, amplifications were performed in 3 batches (batches A-C, containing 102, 119 and 10 experimental samples, respectively). To control for batch effects, common RNA pool control samples were amplified and hybridized in each batch. These included LCM extracted hippocampus CA3 samples from the current study and a whole rhesus brain RNA pool (Biochain). These control samples were hybridized in 6 replicates in batch A and B and in 3 replicates in batch C (3 replicates per 96 well plate).

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Dataset Information

Primate brain architecture and selection in relation to sex.

Background

Results

Conclusion

Publications

Primate brain architecture and selection in relation to sex.

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