Question

Question 6 0 / 1 pts Imagine two species that differ in amino acid sequence at a particular locus. The nucleotide diversity for nucleotide sites with synonymous changes equals 0.025 and that for sites with nonsynonymous changes equals 0.01. If there are 8 substitutions at synonymous sites and 4 substitutions at nonsynonymous sites, calculate both the dn/ds ratio and the ratio of the McDonald-Kreitman test . Do the two ratios lead to different conclusions with respect to the nature of natural selection (being purifying selection of positive selection)