Exons

DNA is made up of different units called nucleotides. There are a variety of four different nucleotides that make up the polymer that is DNA^[1]. DNA consists of two different regions, one being exons and the other introns. The regions of exons in the DNA consist of fewer nucleotides than the regoins of introns and are the regions that code for proteins^[2]. It is also now thought that enhancer sequences for regulation of gene transcription is not just found in introns but also exons.^[3].

References

1. ↑ Alberts .B. (2008) Molecular Biology of the Cell, 5th Edition, New York: Garland Science
2. ↑ Gilbert W, 1978 "Why genes in pieces?", Nature, 271 (5645): 501
3. ↑ Purnel;, B. Exons. Exons Encode Enhancers. Science 2012. Vol:336(6079), pp.277-277