Exon / Intron
structure of some vertebrate genes
In eukaryotes, the intervening
introns separate the expressed
exon regions. Intron /
Exon organization varies widely among genes: a single intron
may constitute a minority of the locus, as in insulin, or
multiple introns may make up a majority of the sequence, as in ovalbumin.
The ovalbumin gene was the first gene in which the intron / exon
structure was discovered. Some genes are millions of bp in
length, and contain dozens of introns that constitute >99%
of the sequence.