Analysis of somatic mutations in the aging human brain using single-cell whole genome sequencing

 描述（由申请人提供）：虽然正常性状和疾病易感性的大部分人类变异受遗传性遗传变异控制，包括以孟德尔方式遗传的变异和在亲本配子发生中发生的从头突变，但体细胞突变越来越被认为是决定人类表型的强大力量。然而，我们缺乏对体细胞突变的全面了解，因为到目前为止，技术限制阻止了对低嵌合基因组变异的检查。我们的实验室已经开发出新的技术，使我们能够通过对单个人类死后神经元细胞核进行全基因组测序来以前所未有的分辨率检查体细胞嵌合现象。我已经使用这种技术对来自一个正常的17岁个体的死后人类神经元中的体细胞突变进行了广泛的表征。在这个应用程序中，我建议扩展这个分析，以测试的假设，体细胞突变积累随着年龄的增长，在人类大脑。问题：体细胞突变的负担是否随着年龄的增长而增加，这表明它可能是衰老的一种机制？衰老是一个生物学过程，其特征是细胞、组织和器官水平的逐渐退化，与年龄相关的认知能力下降是老年人的主要健康问题。神经元是长寿的和有丝分裂后的，因此作为一个个体，神经元有很长的时间暴露于遗传毒性损伤，如氧化或放射性损伤，并因此获得突变。因此，随着年龄的增加，有丝分裂后神经元中的体细胞突变的数量也可能增加。因此，我将确定年龄和体细胞镶嵌之间是否存在相关性。由于特定的突变过程会引起特征性的签名改变，通过识别哪些类型的突变随着年龄的增长而积累，我将定义一个候选过程列表。 这可能导致大脑老化。

 DESCRIPTION (provided by applicant): While a large part of human variation in both normal traits and disease susceptibility is controlled by inherited genetic variation, including variants inherited in a Mendelian fashion and de novo mutations which occur in parental gametogenesis, somatic mutation is increasingly being appreciated as a powerful force which determines human phenotypes. However, we lack a global understanding of somatic mutation because until now technological limitations have prevented examination of low mosaicism genomic variants. Our lab has developed novel techniques which allow us to examine somatic mosaicism at unprecedented resolution by performing whole genome sequencing on single human postmortem neuronal nuclei. I have used this technology to perform extensive characterization of somatic mutations in postmortem human neurons from a normal 17 year old individual. In this application, I propose to extend this analysis to test the hypothesis that somatic mutations accumulate with age in the human brain. Question- Does the burden of somatic mutations increase with age, indicating that it may be a mechanism of aging? Aging is a biological process characterized by the gradual deterioration at the cell, and tissue and organ level, and age-related cognitive decline is a major health concern for the elderly. Neurons are long-lived and post-mitotic, and thus as an individual ages neurons have an extended period of time to be exposed to genotoxic insults, such as oxidative or radiological damage, and as a result acquire mutations. Thus, as age increases so might the number of somatic mutations in post-mitotic neurons. Therefore, I will determine whether a correlation exists between age and somatic mosaicism. Since specific mutational process induce characteristic signature alterations, by identifying which types of mutations accumulate with age, I will define a candidate list of process which may causal in aging in the brain.