what is alternative splicing?
Alternative splicing refers to the production of multiple transcript isoforms from a single gene, due to variations in the splicing reaction of pre-mRNA. Most genes in eukaryotic genomes consist of exons and introns. After transcription, introns need to be removed from the pre-mRNA by a step called splicing. However, sometimes an exon can be either included or excluded from the final transcripts. Or there can be two splice sites at one end of an exon which can be recognized by the spliceosome ( the complex which carries splicing reaction). All these will lead to the production of multiple transcripts and are termed as “alternative splicing”. Alternative splicing has long been regarded as a rather rare event in eukaryotic genomes. For example, it was estimated to occur in less than 5% of human genes. However, recent genomic and bioinformatic analyses of vast amount of transcript data in human and other organisms suggest that alternative splicing is widespread in mammalian genomes. In hu
