exon

¹

[ ek-son ]

noun

1. (in Britain) one of four yeomen of the guard who act as commanding officers in the absence of higher authority.

exon

²

[ ek-son ]

noun

, Genetics.

1. any portion of an interrupted gene that is represented in the RNA product and is translated into protein.

exon

¹

/ ˈɛksɒn /

noun

1. one of the four officers who command the Yeomen of the Guard

exon

²

/ ˈɛksɒn /

noun

1. See intron
   any segment of a discontinuous gene the segments of which are separated by introns Compare intron

exon

/ ĕk′sŏn /

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.
2. Compare intron

exon

1. 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 .)

Derived Forms

• exˈonic, adjective

Word History and Origins

Origin of exon¹

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

Origin of exon²

1975–80; ex(pressed sequence) + -on ¹

Word History and Origins

Origin of exon¹

C17: a pronunciation spelling of French exempt exempt

Origin of exon²

C20: from ex- ¹+ -on

Example Sentences

As introns are removed during splicing, one exon also gets axed from the resulting SMN2 RNA—exon 7.

From Nautilus

Scientists took a few hundred thousand random molecules and tested each one in cells to see which ones increase SMN2 exon 7 splicing.

From Nautilus

Although the final drug, Evrysdi, is safe and effective, scientists are still debating how it functions at the molecular level—in particular, how it singles out SMN2 exon 7 among the vast number of other exons.

From Nautilus

The cell then snips out these extraneous bits, leaving only exons to form mature RNA that can make proteins.

From Singularity Hub 

In 1837 he was appointed exon of the Yeomen of the Guard, which he held up to 1849.

From Project Gutenberg

Exon librum istum cum pari suo, in festo Annuntiationis Dominice.

From Project Gutenberg

But, it will be seen, the 'tenuit' of Domesday is equated by the 'emit' of the Exon book.

From Project Gutenberg

We have not seen dominicum used as a substantive; but in the Exon.

From Project Gutenberg

I do not believe that there could be found under heaven another man like this exon.

From Project Gutenberg