Alternative splicing in eukaryotes: the norm, not an anomaly

摘要

In eukaryotic organisms, protein-coding regions are fragmented into several parts (exons) on the genome, which are separatee by long stretches of non-coding regions (introns). The spliceosome handles the task of splicing out the introns and reassembling the exons together to form translatable mRNAs. It has been known lor the last several decades that the spliceosome is capable of assembling exons alternatively to create distinct mRNA species. Considering that human genes, on an average, contain 7-8 exons, alternatne splicing should have been anticipated to be the norm. But until the turn of the 21st century, alternative splicing was considered nature's anomaly, affecting less than 5% of the human genes.