Wiktionary
exons
n. (plural of exon English)
Usage examples of "exons".
The very first genes would have had to come from random DNA, since there were no genes or exons to be duplicated or crossed-over in meiosis.
The coding region of a gene is fragmented into little pieces, called exons, linked by long stretches of non-coding DNA, or introns.
Only when messenger RNA is made during a process called transcription are the exons spliced together.