Intron / Exon Structure of a eukaryotic gene
The mRNA message for ovalbumin was hybridized with the the ssDNA template strand from which it was transcribed. Instead of a one-to-one colinear pairing as expected, the ssDNA "loops out" in order to pair with the mRNA. This indicates that the structure of the gene is a series of exons (1 - 7, above) that are expressed in the mRNA, separated by a series of intervening introns (A - G) that have been "spliced out" of the hnRNA. The mature mRNA is 1872bp long: introns make up >75% of the length of the gene.
Figure © 2000 by Griffiths et al. ; text © 2008 by Steven M. Carr