Question

An adult with a history of tanning has his genome sequenced. The beginning of a protein-coding region of his DNA reads ATGGGGATATGGCAT. If the protein-coding region of a healthy adult reads ATGGGGATATGAGCAT, identify the site and type of mutation.

a) Missense mutation at the second codon, changing from glycine to serine.
b) Nonsense mutation at the third codon, leading to premature termination.
c) Silent mutation at the fifth codon, causing no change in the amino acid sequence.
d) Frameshift mutation at the fourth codon, altering subsequent amino acids.

Answer 1

The DNA sequence change from ATGGGGATATGAGCAT to ATGGGGATATGGCAT indicates a missense mutation at the second codon, changing from glycine to serine.

Step-by-step explanation:

An adult with a history of tanning has his genome sequenced, revealing a single nucleotide change in the DNA sequence of a protein-coding region. Comparing the altered sequence ATGGGGATATGGCAT with the healthy sequence ATGGGGATATGAGCAT, we can identify the mutation and its site. By breaking down the sequence into triplets or codons, which represent amino acids, we see a change from GAG to GGC at the fourth codon. This suggests a missense mutation where the fourth codon for the amino acid glutamic acid in the healthy individual is changed to glycine in the individual with a history of tanning.

The correct option, in this case, is (a) Missense mutation at the second codon, changing from glycine to serine.The site of the mutation is the second codon, where a guanine (G) is changed to an adenine (A). The type of mutation is a missense mutation, as it changes the amino acid encoded by the codon. In this case, the missense mutation changes the amino acid from glycine to serine.