RNA-seq, or RNA sequencing, is a powerful technique used to analyze the complete set of RNA molecules in a cell or tissue at a specific time. It allows researchers to measure gene expression levels, identify new genes, and discover alternative splicing events. By converting RNA into complementary DNA (cDNA) and sequencing it, scientists can obtain a detailed snapshot of the active genes in a sample. This method has revolutionized the field of genomics by providing insights into cellular processes and disease mechanisms. RNA-seq is widely used in various applications, including cancer research, developmental biology, and personalized medicine, helping to advance our understanding of complex biological systems.