The heritability of chimpanzee and human brain asymmetry
The heritability of chimpanzee and human brain asymmetry
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DOI：
10.1098/rspb.2016.1319
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发表时间：
2016-12-28
影响因子：
4.7
通讯作者：
Sherwood, Chet C.
中科院分区：
文献类型：
--
作者：
Gomez-Robles, Aida;Hopkins, William D.;Sherwood, Chet C.
人类大脑的结构明显不对称，功能偏侧化，这表明这两种特性之间存在关系。其他密切相关的灵长类动物（例如黑猩猩）的大脑也表现出类似的不对称模式，但程度较轻，这表明在古人类进化过程中解剖和功能不对称性有所增加。我们使用经典形态测量学、几何形态测量学和定量遗传技术分析了黑猩猩和人类大脑不对称的遗传性。在我们的分析中，我们将方向不对称性和波动不对称性（FA）分开，这表明发育过程中的环境影响。我们发现，在通过简单的线性指标测量时，那些始终存在于群体中大多数个体中的不对称方向模式不具有显着的遗传力，但当通过反映不同皮质区域相对于彼此的大小、位置和方向的变化的地标的三维配置进行评估时，它们在人类中具有略微显着的遗传力。此外，人类左右半球之间的遗传相关性远低于黑猩猩，这表明环境对人类左右半球差异的影响相对较强。我们还表明，两个物种的大脑皮层某些区域的 FA 水平都具有显着的遗传性。这表明大脑对环境影响的反应可能反映了神经可塑性，在这两个物种中都有遗传基础。这些结果对人类及其近亲大脑不对称性和可塑性的进化具有影响。
Human brains are markedly asymmetric in structure and lateralized in function, which suggests a relationship between these two properties. The brains of other closely related primates, such as chimpanzees, show similar patterns of asymmetry, but to a lesser degree, indicating an increase in anatomical and functional asymmetry during hominin evolution. We analysed the heritability of cerebral asymmetry in chimpanzees and humans using classic morphometrics, geometric morphometrics, and quantitative genetic techniques. In our analyses, we separated directional asymmetry and fluctuating asymmetry (FA), which is indicative of environmental influences during development. We show that directional patterns of asymmetry, those that are consistently present in most individuals in a population, do not have significant heritability when measured through simple linear metrics, but they have marginally significant heritability in humans when assessed through three-dimensional configurations of landmarks that reflect variation in the size, position, and orientation of different cortical regions with respect to each other. Furthermore, genetic correlations between left and right hemispheres are substantially lower in humans than in chimpanzees, which points to a relatively stronger environmental influence on left-right differences in humans. We also show that the level of FA has significant heritability in both species in some regions of the cerebral cortex. This suggests that brain responsiveness to environmental influences, which may reflect neural plasticity, has genetic bases in both species. These results have implications for the evolvability of brain asymmetry and plasticity among humans and our close relatives.