_______ Tend(s)to Occur More Frequently Than ________

Question

_______ tend(s)to occur more frequently than ________.
A)Synonymous substitutions,nonsynonymous substitutions
B)Genetic divergence,genetic convergence
C)Transitions,transversions
D)A and B only
E)A,B,and C

Accepted Answer

A) Synonymous substitutions tend to occur more frequently than nonsynonymous substitutions because they do not change the amino acid and thus are less likely to be deleterious. B) Genetic divergence tends to occur more frequently than genetic convergence because random mutations and selection pressures usually lead to species becoming more different over time. C) Transitions (substitutions between two purines or two pyrimidines) are more common than transversions (substitutions between a purine and a pyrimidine) due to the chemical similarity and stability of the changes within the same class of nucleotides.