True or False 

A dN/dS value of > 1 is indicative of positive selection and a value < 1 is indicative of neutrality.

A researcher has obtained the following counts of mutations by comparing DNA sequences from two different species and by comparing DNA sequences from two different species and by comparing a set of DNA sequences sampled from several individuals within the same species:

A) Using only Divergence data, is there evidence of positive selection for amino acid change?

B) Use these data to perform a McDonald-Kreitman test.

C) Is there evidence of natural selection in this gene? Why?

D) Which of the following factors might explain the results and why?

a) Recurrent positive selection

b) Negative selection

c) Balancing selection

d) Neutrality

Please show all work and explain all steps!

You are making a knockout mouse, after neomycin (positive) selection you treat the surviving cells with gancyclovir (negative selection) and more cells die. What does cell death after gancyclovir treatment indicate?