Mutations in the third position of codons are the least likely to affect the amino acid sequence.Mutations in the second position are most likely to change the amino acid sequence, whereas first-position mutations are intermediate.Based on what you know about molecular evolution, predict the relative rates of evolution for first-, second-, and third-position codon nucleotides, from least likely to most likely.

Question

Quizplus · Accepted Answer

Third-position mutations are the most likely to be silent or synonymous, not affecting the amino acid sequence, and thus can accumulate at a higher rate. First-position mutations have an intermediate effect, while second-position mutations are most likely to alter the amino acid, being more subject to selective pressure and evolving more slowly.

Mutations in the Third Position of Codons Are the Least