Heritability of lobar brain volumes in twins supports genetic models of cerebral laterality and handedness
Heritability of lobar brain volumes in twins supports genetic models of cerebral laterality and handedness
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DOI：
10.1073/pnas.052494999
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发表时间：
2002-03-05
影响因子：
11.1
通讯作者：
Carmelli, D
中科院分区：
文献类型：
--
作者：
Geschwind, DH;Miller, BL;Carmelli, D
虽然人类大脑左右半球在功能和解剖学上都有差异，但人们对控制中枢神经系统不对称的环境或遗传因素知之甚少。然而，大脑的不对称性与用手习惯密切相关，而且用手习惯确实有重要的遗传成分。为了探讨环境和遗传对大脑不对称性的相对影响，我们检查了一个大型队列的老年同卵和异卵双胞胎的左右大脑皮层的体积，并探讨了它们与利手的关系。脑叶体积有一个主要的遗传成分，这表明基因在随着年龄的增长而发生的脑体积变化中起着重要作用。共同的环境，可能代表子宫内的事件，对左半球的影响大约是右半球的两倍，这与左半球的遗传控制较少相一致。为了检验惯用手和大脑不对称性的主要遗传模型，双胞胎被分为两个右利手和至少一个左利手（非右利手）。遗传因素对左右半球体积的影响是右利手双胞胎的两倍，这表明在非右利手双胞胎中，大脑体积的遗传控制有很大的减少。这种非右利手双胞胎左右大脑半球遗传决定的丧失与假设右利手左半球偏向遗传影响的模型一致，即非右利手双胞胎中失去的“右移”基因型，导致大脑不对称性降低。
Although the left and right human cerebral hemispheres differ both functionally and anatomically, little is known about the environmental or genetic factors that govern central nervous system asymmetry. Nevertheless, cerebral asymmetry is strongly correlated with handedness, and handedness does have a significant genetic component. To explore the relative contribution of environmental and genetic influences on cerebral asymmetry, we examined the volumes of left and right cerebral cortex in a large cohort of aging identical and fraternal twins and explored their relationship to handedness. Cerebral lobar volumes had a major genetic component, indicating that genes play a large role in changes in brain volume that occur with aging. Shared environment, which likely represents in utero events, had about twice the effect on the left hemisphere as on the right, consistent with less genetic control over the left hemisphere. To test the major genetic models of handedness and cerebral asymmetry, twin pairs were divided into those with two right handers and those with at least one left hander (nonright handers). Genetic factors contributed twice the influence to left and right cerebral hemispheric volumes in right-handed twin pairs, suggesting a large decrement in genetic control of cerebral volumes in the nonright-handed twin pairs. This loss of genetic determination of the left and right cerebral hemispheres in the nonright-handed twin pairs is consistent with models postulating a right-hand left-hemisphere-biasing genetic influence, a "right-shift" genotype that is lost in nonright handers, resulting in decreased cerebral asymmetry.