Alternative splicing is a cellular process that occurs during gene expression, where exons from the same gene are joined in different combinations, leading to different but related mRNA transcripts. This process allows a single gene to code for multiple proteins, increasing the number of proteins that can be encoded by the genome. Alternative splicing occurs in both protein-coding genes and non-coding genes to produce multiple products (proteins or non-coding RNAs) . The process of alternative splicing lets different exons be connected in different ways, allowing for the creation of hundreds of combinations of a protein from a single gene.

Alternative splicing is a central element in gene expression, and it has a role in almost every aspect of protein function, including binding between proteins and ligands, nucleic acids or membranes, localization, and enzymatic properties. Genuine alternative splicing occurs in both protein-coding genes and non-coding genes to produce multiple products (proteins or non-coding RNAs) .

Alternative splicing may provide evolutionary flexibility, as a single point mutation may cause a given exon to be occasionally excluded or included from a transcript during splicing, allowing production of a new protein isoform without loss of the original protein. Alternative splicing is a vital mechanism in gene modulation, allowing a single gene to produce multiple distinct mRNA that greatly increase transcriptome and proteome diversity.

The five basic modes of alternative splicing are generally recognized: exon skipping, mutually exclusive exons, alternative 5ss, alternative 3ss, and intron retention. Alternative splicing is controlled by cis-regulatory elements and trans-acting factors.

Aberrant alternative splicing can lead to various neurological diseases and cancers and is responsible for aging, infection, inflammation, immune and metabolic disorders, and so on. Therefore, alternative splicing is a promising therapeutic target for various diseases.