Genomics and Applied Biology 2024, Vol.15, No.1, 39-46 http://bioscipublisher.com/index.php/gab 40 provide useful references and insights for advancing the field of neuroscience, as well as pave new paths for the effective prevention and treatment of neurological disorders. 1 Single-Cell Omics Characteristics in Neuroscience 1.1 Heterogeneity of neuronal cells The heterogeneity of neuronal cells is one of the core characteristics of the nervous system, which bestows the brain with unparalleled complexity and functionality. This heterogeneity is reflected at multiple levels including the morphology, structure, electrophysiological properties, and molecular composition of neuronal cells. At the genomic level, the heterogeneity of neuronal cells manifests as variability and complexity in gene expression across different cell types (Song et al., 2020). The nervous system contains various cell types, including neurons, astrocytes, oligodendrocytes, and microglia, each exhibiting significant genomic heterogeneity. For example, neurons are responsible for the transmission and processing of information, and their genomes contain numerous genes related to synaptic transmission, ion channels, and the synthesis and release of neurotransmitters. In contrast, glial cells mainly provide support, protection, and nourishment to neurons, and their genomes are enriched with genes related to metabolism, immunity, and repair (Tavakolian-Ardakani et al., 2019). Furthermore, even within the same type of neuron, genomic characteristics can vary between different brain regions and developmental stages. For instance, dopaminergic neurons play crucial roles in motor control, emotional regulation, and cognitive functions, containing numerous genes associated with these functions. However, the expression patterns and regulatory mechanisms of these genes can differ among dopaminergic neurons in different brain areas. 1.2 Overview of single-cell technologies Single-cell omics technologies are methods capable of deeply investigating molecular information such as the genome, transcriptome, and epigenome at the level of individual cells. The advent of these technologies has enabled a more detailed understanding of the heterogeneity among different cell types within an organism, as well as the molecular mechanisms of cells under physiological and pathological conditions (Clark et al., 2018). Single-cell omics primarily includes single-cell sequencing and single-cell epigenomics. Single-cell sequencing technology allows for high-throughput sequencing of the genome or transcriptome of individual cells, revealing each cell's gene expression profile and variations (Jeongwoo et al., 2020). On the other hand, single-cell epigenomics focuses on studying the chromatin structure, DNA methylation, and histone modifications of individual cells, which are crucial for understanding cell differentiation, development, and disease mechanisms (Figure 1). Hu et al. (2018) summarized the current single-cell multi-omics methods, such as scG&T-seq (single-cell genome and transcriptome sequencing), scMT-seq (single-cell methylome and transcriptome sequencing), scM&T-seq (single-cell methylome and transcriptome sequencing), scTrio-seq (single-cell tri-omics sequencing), and scCOOL-seq (single-cell chromatin overall landscape sequencing), and measured different combinations of omics data (Figure 1). The basic principle involves isolating individual cells, lysing them, and tagging molecules, followed by high-throughput sequencing and analysis of these molecular data. The workflow typically includes steps such as cell isolation, reverse transcription and amplification, library construction, sequencing, and data analysis. Among these, cell isolation is a crucial first step, which can be achieved through methods such as flow cytometry, micromanipulation, or tissue digestion. 1.3 The role of single-cell genomics in neurogenesis and neurodegenerative diseases Single-cell genomics offers a unique perspective and powerful tools for revealing the molecular mechanisms behind neurogenesis, synaptic plasticity, and neurodegenerative diseases. During neurogenesis, single-cell genomics can intricately depict how neural stem cells gradually differentiate into various types of neurons and glial cells, along with the dynamic changes in gene expression during these processes. By analyzing the genomic,
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