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Definition

noun, plural: exons

(molecular biology)

1. The protein-coding region in the DNA.

2. The nucleic acid sequence in the DNA, or RNA transcript following genetic splicing.

Supplement

Genes contain exons which are regions coding for proteins and which are interrupted by the unused sequences called introns. Exons have been found to include both sequences coding for amino acids and untranslated sequences. The introns are removed and the exons are joined together to form the final functional mRNA.

Related forms: exonic (adjective).
Compare: intron.
See also: DNA, RNA, translation, mRNA, protein synthesis.