Cell Identity Determination In Human Brain: Somatic Mutation and Cell Lineage

体细胞突变，存在于大脑的一些细胞中，但不是所有的细胞中，越来越多地涉及到 神经和精神疾病。产前脑细胞分裂过程中出现的体细胞突变 发育是以克隆方式遗传的，可导致神经发育疾病，如癫痫和 智力残疾，即使存在于低水平的马赛克。这笔赠款的上一个资助期 开发了新的方法和算法来分析死后人脑的体细胞突变，以及 对单个神经元的基因组进行排序的技术，并表明每个神经元都有一个独特的 基因组，出生时存在数百个发育突变，还增加了数十个突变 生命的每一年。在出生前，2-3个突变标志着每个细胞分裂，因此突变使 校长有每个细胞分裂的永久记录.将细胞谱系DNA标记分析与 识别人脑中不同神经类型的基因表达模式现在可能使 发现产生人类细胞的细胞分裂模式的第一张系统图 大脑。在这个项目中，我们将应用我们现有的方法来提供几个独一无二的科学发现 可实现的，为遗传学和神经科学界提供广泛实用的工具。 我们的三个具体目标将是：1)使用DNA突变和RNA基因的同时分析 表达以绘制大脑皮层神经细胞类型的谱系；2)绘制表面的克隆模式 以了解它们与大脑皮层功能细分的关系；以及3)专注于 分析人类颞叶的发育，它受制于许多独特的条件，如颞叶 癫痫。 这些数据提供了三个主要发现，它们都是神经科学的主要目标，并且 目前还不能通过其他方式获得：1)来自成人大脑的第一个直接细胞谱系数据，2) 连接神经元细胞类别的初步谱系图，以及3)对颞叶的独特洞察 发展。

Somatic mutations, present in some but not all cells of the brain, are increasingly implicated in neurological and psychiatric diseases. Somatic mutations that arise during the cell divisions of prenatal brain development are inherited in clonal fashion and can cause neurodevelopmental diseases such as epilepsy and intellectual disability, even when present at low levels of mosaicism. The previous funding period of this grant developed new methods and algorithms to analyze somatic mutations in postmortem human brain, and technologies to sequence the genomes of single neurons, and has shown that each neuron has a unique genome, with hundreds of developmental mutations present at birth, and dozens more mutations being added each year of life. During prenatal life, 2-3 mutations mark each cell division, so that mutations make in principal a permanent record of each cell division. Integrating the analysis of DNA marks of cell lineage with patterns of gene expression that identify the different neural types in human brain potentially now enables the discovery of the first systematic picture of the pattern of cell divisions that generates the cells of the human brain. In this project, we will apply our existing methods to provide several scientific discoveries not otherwise attainable, providing tools of widespread utility to the genetics and neuroscience communities. Our three Specific Aims will be to 1) use simultaneous analysis of DNA mutations and RNA gene expression to map the lineage of neural cell types in cerebral cortex; 2) map clonal patterns across the surface of the human cerebral cortex to see how they relate to functional subdivisions of the cortex; and 3) focus on the analysis of development of human temporal lobe, which is subject to many unique conditions like temporal lobe epilepsy. These data provide three major discoveries which have all been major goals of neuroscience and which are not presently obtainable by other means: 1) the first direct cell lineage data from the adult human brain, 2) a preliminary lineage map connecting neuronal cell classes, and 3) unique insight into temporal lobe development.