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exon1

[ek-son]
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noun
  1. (in Britain) one of four yeomen of the guard who act as commanding officers in the absence of higher authority.
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Origin of exon1

1645–55; earlier exant, for French exempt (spelling altered to show French pronunciation)
Also called exempt.

exon2

[ek-son]
noun Genetics.
  1. any portion of an interrupted gene that is represented in the RNA product and is translated into protein.
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Compare intron.

Origin of exon2

1975–80; ex(pressed sequence) + -on1
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

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British Dictionary definitions for exon

exon1

noun
  1. British one of the four officers who command the Yeomen of the Guard
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Word Origin

C17: a pronunciation spelling of French exempt exempt

exon2

noun
  1. any segment of a discontinuous gene the segments of which are separated by intronsCompare intron
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Derived Formsexonic, adjective

Word Origin

C20: from ex- 1 + -on
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

exon in Medicine

exon

(ĕksŏn)
n.
  1. A nucleotide sequence in DNA that carries the code for the final mRNA molecule and thus defines a protein's amino acid sequence.coding sequence
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Related formsex•onic adj.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

exon in Science

exon

[ĕksŏn]
  1. A segment of a gene that contains information used in coding for protein synthesis. Genetic information within genes is discontinuous, split among the exons that encode for messenger RNA and absent from the DNA sequences in between, which are called introns. Genetic splicing, catalyzed by enzymes, results in the final version of messenger RNA, which contains only genetic information from the exons. Compare intron.
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The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

exon in Culture

exon

Stretches of DNA in genes that code for proteins. In eukaryotes, exons in a given gene are generally separated from each other by stretches of DNA that do not contain instructions for constructing proteins. (Compare intron.)

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The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.