Question

Suppose that there is a frameshift mutation between the 10^th and 11^th base (counting from the left: a Guanine is added) in the minus strand of DNA, finish the table giving the resulting peptide. Circle the changes in the resulting peptide caused by the mutation. What is the importance of these changes. (Assume the reading frame starts with the first codon)

Answer 1

TABLE 1: NORMAL STRAND

(Non coding strand) MINUS STRAND: 3' TAC CTA CTT ccC GCA ACT 5'

(coding strand )Positive strand: : 5' ATG GAT GAA GGG CGT TGA 5'

m RNA (CODONS): 5' AUG GAU GAA GGG CGU UGA 3'

Amino Acids: Met-Asp-Glu-Gly-Arg

tRNA: 5 required (No tRNA for UGA)

TABLE 2: MUTATED STRAND

Mutated Minus strand: 3' TAC CTA CTT CGC CGC AAC T 5'

Mutated Positive strand: 5' ATG GAT GAA GCG GCG TTG A3'

mRNA (Codons): 5' AUG GAU GAA GCG GCG UUG A5'

Amino Acids:Met-Asp-Glu-Ala-Ala-Leu

tRNA:6 required(Stop codon missing)