Introns, erived from the term "intragenic regions", are non-coding sections of precursor mRNA (pre-mRNA) or other RNAs, that are removed (spliced out of the RNA) before the mature RNA is formed. Once the introns have been spliced out of a pre-mRNA, the resulting mRNA sequence, composed of exons, is ready to be translated into a protein. The corresponding parts of a gene are known as introns as well.