INTRON REMOVAL. Genetic “information is transcribed from DNA into a messenger RNA (mRNA) template by a process called transcription. However, in eukaryotes, before the mRNA can be translated into proteins, non-coding portions of the sequence, called introns, must be removed and protein-coding parts, called exons, joined by RNA splicing to produce a mature mRNA.”
http://bitesizebio.com/10148/what-is-alternative-splicing-and-why-is-it-important/