4. Rate of substitution.
The Galapagos National Park has charged you with determining when two populations of the Galapagos hawk have diverged from one another from a common ancestral population, because one hawk population is doing well and the other is close to extinction. The National Park is considering augmenting (adding to) the population of one with individuals from the other. So, you calculations really matter, if the populations
diverged relatively recently the Park is less concerned about mixing the populations, but if the split between the two populations happened long ago, they will be more concerned and may need to look to other island populations to rescue the endangered one. The hawk's genome size is 1 x 109 base pairs, and the mutation rate is 1 base change/1.0 x 108 sites/generation. There is 1 hawk generation per year. You are studying populations that have colonized two different islands. You find that in neutral regions of the hawk's genome, the sequences differ at 0.5% of the sites.

a. Use these figures to find out an expected time of divergence of the two hawk populations. (Remember that two hawk populations are evolving from the ancestral state; their divergence will be the sum of evolution in both populations-you'll have to divide by half at some point in your calculations!).

b. As we noted, one of the hawk populations is on a small island and has a small population size compared to the other island, which is much larger. Does this affect your
calculations? describe briefly.

c. You observe that the extent of divergence is only 0.05% in a region of the genome that encodes protein subunits of the ribosomal complex, an essential cell component. What is the most likely explanation for lower divergence in this region?