In which cellular processes is cDNA commonly utilized?

cDNA, or complementary DNA, is primarily used in the context of gene expression analysis. This process involves the synthesis of cDNA from messenger RNA (mRNA) through the action of the enzyme reverse transcriptase. By converting mRNA into cDNA, researchers can study the expression levels of specific genes in various tissues or under different environmental conditions. This is particularly useful because cDNA represents the coding sequences of genes that are actively expressed in a sample at a given time.

In gene expression analysis, cDNA can be used to create libraries, perform quantitative PCR (polymerase chain reaction), and conduct microarray experiments. These methods help in understanding which genes are being expressed and at what levels, providing insights into cellular activities and responses to stimuli.

The other processes listed do not rely on cDNA in the same primary way. DNA replication is the process of copying DNA, protein synthesis involves translating mRNA into proteins, and RNA splicing is a modification of mRNA before it is translated into protein. None of these processes utilize cDNA as a fundamental component like gene expression analysis does.