Chapter 1, Problem 15P

Mutations in genes that change their pattern of expression (the time and cell type in which the gene product is produced) are thought to be a major factor in the evolution of different organisms. Would you expect the same protein to work in the same way (for example, to perform the same kind of enzymatic reaction) in two different types of cells (for example, cells in the retina of the eye and muscle cells)? Is it possible that the same protein might function in different biochemical pathways in eye cells and muscle cells even if the protein’s basic mechanism always remains the same?