Department of Neurology, Kennedy Krieger Institute, Baltimore, Maryland 21205, USA; email:
Program in Biochemistry, Cellular, and Molecular Biology, Johns Hopkins School of Medicine, Baltimore, Maryland 21287, USA; email:
Annu Rev Genet. 2020 Nov 23;54:487-510. doi: 10.1146/annurev-genet-041720-093403. Epub 2020 Sep 11.
Mosaicism refers to the occurrence of two or more genomes in an individual derived from a single zygote. Germline mosaicism is a mutation that is limited to the gonads and can be transmitted to offspring. Somatic mosaicism is a postzygotic mutation that occurs in the soma, and it may occur at any developmental stage or in adult tissues. Mosaic variation may be classified in six ways: () germline or somatic origin, () class of DNA mutation (ranging in scale from single base pairs to multiple chromosomes), () developmental context, () body location(s), () functional consequence (including deleterious, neutral, or advantageous), and () additional sources of mosaicism, including mitochondrial heteroplasmy, exogenous DNA sources such as vectors, and epigenetic changes such as imprinting and X-chromosome inactivation. Technological advances, including single-cell and other next-generation sequencing, have facilitated improved sensitivity and specificity to detect mosaicism in a variety of biological contexts.
镶嵌现象是指个体的基因组来自单一受精卵，却包含两种或两种以上的基因组。种系镶嵌现象是一种局限于生殖腺的突变，能够遗传给后代。而体镶嵌现象是一种合子后突变，发生在体细胞中，可能出现在任何发育阶段或成人组织中。镶嵌现象的变异可以通过以下六种方式分类：（1）种系或体细胞起源，（2）DNA 突变的类别（从单个碱基对到多个染色体不等），（3）发育背景，（4）身体位置，（5）功能后果（包括有害、中性或有利），以及（6）镶嵌现象的其他来源，包括线粒体异质性、载体等外源 DNA 来源以及印迹和 X 染色体失活等表观遗传变化。技术进步，包括单细胞和其他下一代测序技术，提高了在各种生物背景下检测镶嵌现象的灵敏度和特异性。
