What are the functions of introns?

Although introns do not encode protein products, they have very important biological functions, for example:

• The most important function of introns is that they allow for alternative splicing, making it possible to generate multiple proteins from a single gene.
• Some introns encode functional RNA molecules through further processing after they are spliced.
• Introns also play essential roles in gene expression regulation such as nonsense-mediated decay and mRNA export.