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The following is the DNA sequence of the entire protein-coding region for some s

ID: 227269 • Letter: T

Question

The following is the DNA sequence of the entire protein-coding region for some small gene in a eukaryote. Shown is the coding strand. The first row is the original sequence with no mutations. Subsequent rows represent a single mutation.

Mutation                                                        DNA Sequence

None 5’ ..A T G C T G A G C C G C G G C T G A.. 3’

A) 5’ ..A T G C T G A G A C G C G G C T G A.. 3’

B) 5’ ..A T G C T G A G C C G C G G T T G A.. 3’

C) 5’ ..A T G C T G G G C C G C G G C T G A.. 3’  

The region without a mutation is transcribed, and then translated. Give the protein that is translated from this section of DNA. Use the single letter abbriviations for amino acids with no spaces.

N-___?__-C

Determine the molecular basis for each mutation and what effect there would be on the protein.

Mutation Molecular Basis                      Effect on Protein

A) transition or transversion                  nonsense, synonymous, nonsynonymous, readthrough

B) transition or transversion                  nonsense, synonymous, nonsynonymous, readthrough

C) transition or transversion                nonsense, synonymous, nonsynonymous, readthrough

Explanation / Answer

A. Transversion, change of amino acid from serine to argenine, therefore nonsynonymous mutation.

B. Transition, synonymous (glycine)

C. Transition, nonsynonymous (ser to gly)

Protein sequence from the unmutated region:

MLSNG