An intron is a portion of a gene that does not code for amino acids. In the cells of plants and animals, most gene sequences are broken up by one or more introns. The parts of the gene sequence that are expressed in the protein are called exons, because they are expressed, while the parts of the gene sequence that are not expressed in the protein are called introns, because they come in between the exons.
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Introns are very large chunks of RNA within a messenger RNA molecule that interfere with the code of the exons. And these introns get removed from the RNA molecule to leave a string of exons attached to each other so that the appropriate amino acids can be encoded for.
Elliott Margulies, Ph.D.
Investigator, Genome Technology Branch; Head, Genome Informatics Section
Dr. Margulies develops bioinformatical approaches to identifying and characterizing regions of the human genome that are evolutionarily conserved across multiple species. The conservation of these sequences over millions of years of evolution is strong evidence that they play important roles in biology, such as coding for genes or functioning as regulatory elements. He has played an important role in advancing the goals of the NIH Intramural Sequencing Center (NISC) Comparative Sequencing Program. Dr. Margulies's group utilizes both high-performance computational analyses and laboratory-based high-throughput genomic methods to decipher the genetic information that confers biological function.