Single-Cell Transcriptomics

The single-cell transcriptome is the set of messenger RNA (mRNA) molecules expressed in one cell, and it can vary due to external environmental conditions and cellular stage. The transcriptome defines a cell’s function and makes it different from other cells, giving rise to biological heterogeneity. This biological system is comprised of a multitude of different cells with different genotypes and phenotypes that are biochemically and functionally diverse. Traditionally, most genetic studies have analyzed pools of several thousands of cells, which provided information on only average gene expression levels. This approach vastly limits the study of unique cellular signatures of individual cells. Recently, single-cell technologies have been developed, and they have become a powerful approach for a more detailed understanding of biological systems at single-cell resolution. The detection of gene expression variations greatly helped with resolving healthy and diseased cell states. The single-cell transcriptome is currently used in multiple research fields, such as immunology, stem cell research, and cancer biology. This chapter explores the biological applications of the single-cell transcriptome, recent advances in single-cell studies, and the current state of single-cell techniques. Understanding the biological implications of high variability in biological systems will lead to a more precise approach for the development of novel diagnosis and therapy tools.