In a sequence of DNA taken from various species of snails, researchers have found that the rates of nonsynonymous substitutions and synonymous substitutions are roughly the same. What can we infer from this pattern?
A) Transversions are more common than transitions.
B) Most of the amino-acid changes are neutral.
C) Strong stabilizing selection is acting on this gene.
D) Strong selection for change is acting on this gene.
E) None of the above

Question

Quizplus · Accepted Answer

If the rate of nonsynonymous substitutions and synonymous substitutions are roughly the same, it suggests that most of the amino-acid changes are neutral, meaning they are not positively or negatively selected for. This pattern is consistent with the neutral theory of molecular evolution, which posits that most mutations have little to no effect on an organism's fitness.

In a Sequence of DNA Taken from Various Species of Snails