Much of the material in this lecture was borrowed from the following site.
Different proteins mutate at different rates.
Science. Volume 274, Number 5287, Issue of 25 Oct 1996, pp. 568-573.
Gene Duplication Provides Template for New Proteins to Evolve
Domains are often contained on Exons. Duplication of an exon leads to duplication of the domain.
Gene and Genomes can duplicate: starting point for evolution of new protein families
Duplication and mutation can explain protein family evolution, but not the immense diverstiy observed in eukaryotic proteins. Domain shuffling = Exon shuffling.
Introns provide site for recombination without worrying about changing reading frames. One explanation for eukaryotes tolerating introns and other ``useless" DNA.
In addition, we can change how we splice mRNA, giving different combinations of proteins from one mRNA.