Fig. 2

Diagrammatic representation of vertebrate (left panel) and invertebrate (right panel) taxon-specific lens crystallins. Note the use of common metabolic enzymes that function as lens crystallin. Ci-βγ-crystallin in the urochordate, Ciona intestinalis, is thought to be ancestral to the βγ-crystallins of vertebrates although C. intestinalis does not have a lens in its larval eye. Enzymes in parenthesis have undergone mutations and lack activity. Reprinted by permission of the publisher from GENE SHARING AND EVOLUTION: THE DIVERSITY OF PROTEIN FUNCTIONS by Joram Piatigorsky, pp. 62 and 64; Cambridge, Mass.: Harvard University Press, Copyright © 2007 by the President and Fellows of Harvard College