Yi Xing's Alternative Splicing and Computational Genomics Blog

Intro: 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 human, it is estimated that alternative splicing occurs in more than 60% of genes. The "one gene, one protein" central dogma, a governing theory of modern molecular biology which has profound impact on biologists' thinking, therefore has to be revisited. As a result, our view towards many biological processes, such as protein interaction, gene expression, has to be adjusted.

Understanding the functional impact of alternative splicing, the regulatory mechanisms that govern RNA splicing, and the role of alternative splicing in genome evolution, has become one of the most challenging and exciting tasks for genomics and bioinformatics in the post-genomic era.

For a vivid illustration about alternative splicing, please check the animation from Exonhit.

Posted by yxing at October 8, 2004 11:19 AM