Genomic mosaicism describes the phenomenon where some but not all cells within a tissue harbor unique genetic mutations. Traditionally, research focused on the impact of genomic mosaicism on clinical phenotype—motivated by its involvement in cancers and overgrowth syndromes. More recently, we increasingly shifted towards the plethora of neutral mosaic variants that can act as recorders of cellular lineage and environmental exposures. Here, we summarize the current state of the field of genomic mosaicism research with a special emphasis on our current understanding of this phenomenon in brain development and homeostasis. Although the field of genomic mosaicism has a rich history, technological advances in the last decade have changed our approaches and greatly improved our knowledge. We will provide current definitions and an overview of contemporary detection approaches for genomic mosaicism. Finally, we will discuss the impact and utility of genomic mosaicism.

基因组嵌合现象描述了组织内的一些但不是所有细胞都具有独特基因突变的现象。传统上，研究重点是基因组嵌合体对临床表型的影响——其动机是其与癌症和过度生长综合征的关系。最近，我们越来越多地转向大量中性嵌合体变体，它们可以作为细胞谱系和环境暴露的记录器。在这里，我们总结了基因组嵌合研究领域的现状，特别强调了我们目前对大脑发育和体内平衡这一现象的理解。尽管基因组嵌合领域有着丰富的历史，但过去十年的技术进步改变了我们的方法并极大地提高了我们的知识。我们将提供基因组嵌合体的当前定义和当代检测方法的概述。最后，我们将讨论基因组嵌合的影响和效用。