What do exons represent in a sequence of DNA?

Exons represent the coding sequences of DNA that are transcribed into messenger RNA (mRNA) and ultimately translated into proteins. In eukaryotic organisms, genes are often composed of both exons and introns, with exons being the segments that contain the actual information for protein synthesis. During the process of RNA splicing, introns (which do not code for proteins) are removed, leaving only the exons to be assembled into a final mRNA product.

This distinction is crucial for understanding gene expression, as exons are directly responsible for the amino acid sequences in proteins, whereas introns are eliminated and do not play a role in this process. Regulatory sequences, on the other hand, are involved in the control of gene expression rather than coding for proteins. Backup copies of DNA are not a recognized feature of DNA structure or function.