Question

Assuming that a given mutation in a population is a nonlethal germ mutation, which of the following types is least likely to affect the gene pool of that population?

a nucleotide deletion

a nucleotide insertion

a nucleotide substitution

none of these

Answer 1

a nucleotide substitution

Explanation: point substitutions often are silent (synonymous) because of the genetic code's redundancy, so they frequently do not change the encoded amino acid or phenotype. Insertions and deletions are much more likely to cause frameshifts or large protein changes and therefore are more likely to alter the gene pool.