How does alternative rna splicing affect gene expression?

RNA splicing was first discovered in 1970s in viruses and subsequently in eukaryotes.  Not long after, scientists discovered alternative patterns of pre-mRNA splicing that produced different mature mRNAs containing various combinations of exons from a single precursor mRNA. The first example of alternative splicing of a cellular gene in eukaryotes was identified in the IgM gene, a member of the immunoglobulin superfamily. Alternative splicing (AS) therefore is a process by which exons or portions of exons or noncoding regions within a pre-mRNA transcript are differentially joined or skipped, resulting in multiple protein isoforms being encoded by a single gene. This mechanism increases the informational diversity and functional capacity of a gene during post-transcriptional processing and provides an opportunity for gene regulation