Answer to Question #145556 in Cell Biology for Unknown

Question

Consider the following pair of wild-type and mutant template strand sequences.

Wild type: 5’ CCAGTATGGCAT 3’
Mutant: 5’ CCAGTACTGGCAT 3’

What are the amino acid sequences coded by both strands? What type of mutation has occurred?

Answer 1

Wild type: 5’ CCA GTA TGG CAT 3’

RNA m:      3’ GGU CAU ACC GUA 5’

RNA t:           ССА GUA UGG CAU

Amino acid:   Pro – Val – Trp – His

Mutant:  5’ CCA GTA CTG GCA T 3’

RNA m: 3’ GGU CAU GAC CGU A 5’

RNA t:       ССА GUA CUG GCA

Amino acid: Pro – Val – Leu – Ala

There was an insertion of the C nucleotide into the DNA sequence between the 6 and 7 nucleotides [6-7ins C]. This led to a shift in the reading frame and the replacement of the two amino acids Trp with Leu and His with Ala.