Gene expression analysis is a scientific method used to study how genes are turned on or off in a cell. This process helps researchers understand which genes are active in different conditions, such as during development, disease, or environmental changes. By measuring the levels of messenger RNA (mRNA) produced from genes, scientists can determine how much of a specific protein is being made. The analysis often involves techniques like RNA sequencing or microarrays, which allow for the comparison of gene activity across various samples. This information is crucial for understanding biological processes and can aid in the development of targeted therapies for diseases like cancer.