Department of Comparative Medicine, Michale E Keeling Center for Comparative Medicine and Research, The University of Texas MD Anderson Cancer Center, Bastrop, TX 78602
Department of Anthropology and Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, DC 20052.
eNeuro. 2021 Dec 14;8(6). doi: 10.1523/ENEURO.0169-21.2021. Print 2021 Nov-Dec.
Determining the impact that the gene has on primate brain morphology can provide insight into the evolution of human cognition and language systems. Here, we tested whether polymorphisms in in chimpanzees account for gray matter volumetric variation in brain regions implicated in language and communication (particularly within the posterior superior temporal gyrus and inferior frontal gyrus). First, we identified the nature and frequencies of single nucleotide variants (SNVs) in in a sample of unrelated chimpanzees ( spp.). Next, we genotyped a subset of SNVs (those important for gene regulation or likely to alter protein structure/function) in a sample of chimpanzees for which T1-structural magnetic resonance imaging scans had been obtained. We then used source-based morphometry (SBM) to test for whole-brain gray matter covariation differences between chimpanzees with different alleles. Finally, using histologic sections of 15 postmortem chimpanzee brains, we analyzed microstructural variation related to polymorphisms in the posterior superior temporal cortex. We found that the SNVs were associated with variation in gray matter within several brain regions, including the posterior superior temporal gyrus (a region associated with language comprehension and production in humans). The microstructure analysis further revealed hemispheric differences in neuropil fraction, indicating that expression may be involved in regulation of processes related to the formation and maintenance of synapses, dendrites, or axons within regions associated with communication.
确定基因对灵长类动物大脑形态的影响，可以深入了解人类认知和语言系统的进化。在这里，我们测试了黑猩猩中是否存在基因中的多态性，这些多态性是否可以解释与语言和交流相关的大脑区域（尤其是后上颞回和下额回）的灰质体积变化。首先，我们在一组无亲缘关系的黑猩猩（ spp.）样本中确定了基因中的单核苷酸变异（SNV）的性质和频率。接下来，我们对一组黑猩猩进行了 SNV 基因分型（那些对基因调控重要或可能改变蛋白质结构/功能的 SNV），这些黑猩猩已经获得了 T1 结构磁共振成像扫描。然后，我们使用基于源的形态计量学（SBM）来测试不同基因等位基因的黑猩猩之间全脑灰质协变差异。最后，使用 15 只黑猩猩死后脑组织的组织学切片，我们分析了与后上颞叶皮质基因多态性相关的微观结构变化。我们发现，SNV 与几个大脑区域的灰质变化有关，包括后上颞回（人类语言理解和产生的相关区域）。微观结构分析进一步显示了神经突分数的半球差异，表明基因表达可能参与了与突触、树突或轴突的形成和维持相关的过程的调节，这些过程与沟通相关的区域有关。
