What is the primary purpose of a DNA microarray?

The primary purpose of a DNA microarray is to determine gene expression in a sample. This technology allows scientists to measure the expression levels of thousands of genes simultaneously within a single experiment. By hybridizing labeled cDNA derived from mRNA in the sample to the probes on the microarray, researchers can identify which genes are actively being expressed and to what extent. This provides valuable insights into the physiological state of the cell, developmental processes, and responses to various conditions, such as stress or disease.

In contrast, amplifying specific DNA sequences is typically achieved through techniques like PCR, which focuses on replicating DNA rather than measuring expression. Detecting specific DNA sequences is also a function of other methods, such as PCR or Southern blotting, which target particular sequences rather than quantifying overall gene expression. Visualizing internal structures of cells falls under microscopic techniques, which do not share the same goals or methods as a DNA microarray.