The following DNA sequence is a simulated gene taken from fish scales. It codes for a pigment, a molecule that causes the scale to have color. Follow the steps of gene expression do discover what color fish your DNA came from.
DNA:
T A C G C T G T G G G A T A G A A A C G C A G T G T A A T C
1. Transcribe the DNA sequence above into a messenger RNA.
mRNA:
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2. Translate the gene by filling in which amino acid each tRNA will drop off.
This string of amino acids can then be folded into a pigment protein. On the next page, you will see the codes for each pigment found in fish scales.
3. Based on your protein, what color was your fish?
PIGMENTS
Red: Met Arg His Ser Glu Ala Cys Ser Asp
Blue: Met Arg His Ser Glu Val Pro Arg Tyr
Green: Met Arg His Ser Glu Val Pro Gly Tyr
Silver: Met Arg His Pro Ile Phe Thr Trp Cys
Gold: Met Arg His Pro Ile Phe Ala Pro His
Bronze: Met Arg His Pro Ile Phe Ala Ser His
Now, we will imagine several different mutations happen to the gene and figure out what effect they have. For each mutation, transcribe the mRNA and translate it into amino acids. The mutated nucleotides are indicated by being underlined.
Mutation 1
DNA:
T A C G C T G T G G G A T A G A A A C G C G G T G T A A T C
mRNA:
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What color is a fish with this mutation?
Mutation 2
DNA:
T A C G C T G T G G G T T A G A A A C G C A G T G T A A T C
mRNA:
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What color is a fish with this mutation?
Mutation 3
DNA:
T A C A C T G T G G G A T A G A A A C G C A G T G T A A T C
mRNA:
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What happens as a result of this mutation? What might a fish with this mutation look like?
If we added or removed a letter, how would that affect the protein produced by a gene?
