BIO208 Mutation
1. 5โA C G G T C T C G G G A C T T C G A T C G 3โ
A point mutation occurs when a G is substituted with a T as shown in bold.
DNA: 5โA C G T T C T C G G G A C T T C G A T C G 3โ
Template 3โ 5โ
U G C A A G A G C C C U G A A C C U A G C
mRNA: 5โ 3โ
Amino
Acids: Cys Lys Ser Pro Glu Pro Ser
a. Fill in the template DNA for the mutated DNA
b. Fill in the mRNA transcribed from the DNA template that has the mutation
c. Translate the mRNA (codon table below)
d. What is the mutation type? (silent, missense, frameshift, nonsense)
missense mutation
e. How would you characterize this change? (example: third position transition)
First position
2. An insertion occurred between the fifth and sixth codons when two new nucleotides were inserted.
Original DNA: 5โ A C G G T C T C G G G A C T T C G A T C G 3โ
Mutant DNA: 5โ A C G G T C T C G G G A C T T G C C G A T C G 3โ
Template 3โ T G C C A G A G C C C T G A A C G G C T A G C 5โ
mRNA 5โ A C G G U C U G G G A C U U G C C G A U C G 3โ
Amino Thr Val Trp Asp Leu Pro Lle
Acids:
a. Fill in the template DNA for the mutant DNA
b. Transcribe the mutant DNA template to mRNA
c. Translate the mRNA to an amino acid sequence using the codon table
d. How would you characterize this change? (example: third position transition)
First position
e. Is this an example of a silent, nonsense, missense, or frameshift mutation?
frameshift mutation
3. The genetic code is a triplet code. What effect would the addition or loss of six
nucleotides have on the reading frame? Explain.
The loss or addition of six nucleotides would cause two amino acids to either be missing or
added in. This would cause the reading frame to still be read corrected for all the rest of the amino acids.
4. The mRNA transcript is 102 nucleotides long. A frameshift mutation occurs at the 85th nucleotide. How
many amino acids will be correct?
