Rank the following one-base point mutations (from most likely to least likely)with respect to their likelihood of affecting the structure of the corresponding polypeptide:
1)insertion mutation deep within an intron
2)substitution mutation at the third position of an exonic codon
3)substitution mutation at the second position of an exonic codon
4)deletion mutation within the first exon of the gene
A) 1, 2, 3, 4
B) 4, 3, 2, 1
C) 2, 1, 4, 3
D) 3, 1, 4, 2
E) 2, 3, 1, 4

Question

Quizplus · Accepted Answer

A deletion mutation within the first exon (4) is most likely to affect the structure because it can cause a frameshift, altering the entire downstream amino acid sequence. A substitution at the second position of an exonic codon (3) is likely to change the amino acid, directly affecting the polypeptide structure. Substitutions at the third position of a codon (2) might not change the amino acid due to the degeneracy of the genetic code, making it less likely to affect the structure. An insertion deep within an intron (1) is least likely to affect the structure since introns are typically removed during RNA splicing and do not encode the polypeptide.

Rank the Following One-Base Point Mutations (From Most Likely to Least