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Questions for Discussion: Molecular Clocks: Proteins That Evolve at Different Rates
When the concept of molecular clocks was first developed, some researchers thought that it might be a relatively straightforward way to place dates on major events in the history of many groups of organisms. Discuss the reasons why, as molecular biologists learned more about the structure and functions of proteins the idea of a single, universal molecular clock had to be discarded. Discuss why it has turned out to be quite useful to have molecular clocks that "tick" at different speeds. In your discussion, compare the kinds of molecular clocks you might look for if you were trying to date the divergence of the ancestors of: a. living great apes b. humans and whales c. mammals and starfish d. animals and plants Explain why mutations accumulate more slowly in the genes that code for histones than in genes that code for fibrinopeptides.
