Description: Differential expression refers to the variation in gene expression levels between different conditions, such as different tissue types, developmental stages, or responses to specific treatments. This phenomenon is crucial for understanding how genes regulate biological processes and how their activity can change in response to internal or external factors. Gene expression is typically measured using techniques such as quantitative PCR or RNA sequencing, which allow for the quantification of messenger RNA (mRNA) produced by a particular gene. Comparing these mRNA levels across different conditions enables the identification of genes that are overexpressed or underexpressed, which can have significant implications in cellular biology, medicine, and biomedical research. Differential expression is fundamental for studying diseases, as it can reveal potential biomarkers and assist in identifying therapeutic targets. Additionally, it provides insights into the molecular mechanisms underlying processes such as cell differentiation, immune response, and tumor progression.
History: Differential expression began to be studied in depth in the late 20th century, with advancements in molecular biology techniques. In 1995, microarray technology was introduced, allowing for the simultaneous assessment of the expression of thousands of genes, revolutionizing how researchers could analyze gene expression under different conditions. Since then, the development of RNA sequencing has provided greater accuracy and depth in differential expression analysis, enabling more complex and detailed studies.
Uses: Differential expression is used in various areas of biology and medicine, including cancer research, where it aims to identify genes that contribute to tumor progression. It is also applied in studies of genetic diseases, neuroscience, and pharmacology, helping to uncover how treatments affect gene expression. Additionally, it is fundamental in developmental biology to understand how genes regulate the formation of tissues and organs.
Examples: An example of differential expression can be observed in breast cancer studies, where genes that are overexpressed in tumors compared to healthy breast tissue have been identified. Another case is the analysis of immune response, where gene expression profiles in activated immune cells are compared to resting cells, revealing key genes involved in the inflammatory response.
