Intron

=Intron=


 * Introns ** are DNA sequences within a gene that do not code for a protein. They are transcribed into eukaryotic pre-mRNA, but removed by splicing in the formation of a mature mRNA. In bacteria, they do not appear at all in mRNA but do in tRNA and rRNA. The term 'intron' is derived from the term //intragenic region //. They may have previously been protein-coding regions but due to the accumulation of mutations, perhaps from transposon activity, they became inactive. Although for a long time classed as 'junk DNA', recent evidence suggests that introns play an important role in gene regulation.

 //See also:// exon