Multiple Choice
Which statement best describes a frameshift mutation?
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17. Mutation, Repair, and Recombination
Types of Mutations
Multiple Choice
Which of the following is an example of a beneficial mutation in humans?
A
A missense mutation in the CFTR gene that leads to cystic fibrosis
B
A mutation in the lactase (LCT) gene that allows adults to digest lactose, improving nutrition in milk-consuming populations
C
A nonsense mutation that introduces a premature stop codon in the dystrophin gene, causing Duchenne muscular dystrophy
D
A trinucleotide repeat expansion in the HTT gene that causes Huntington disease
Verified step by step guidance1
Step 1: Understand what a mutation is — a change in the DNA sequence that can affect gene function. Mutations can be beneficial, neutral, or harmful depending on their effect on the organism.
Step 2: Review each mutation example and identify its impact on human health or physiology. For instance, a missense mutation in the CFTR gene causes cystic fibrosis, which is a harmful condition.
Step 3: Recognize that a nonsense mutation introducing a premature stop codon in the dystrophin gene leads to Duchenne muscular dystrophy, a severe genetic disorder, so this mutation is harmful.
Step 4: Note that a trinucleotide repeat expansion in the HTT gene causes Huntington disease, a neurodegenerative disorder, which is also harmful.
Step 5: Identify that a mutation in the lactase (LCT) gene allowing adults to digest lactose is beneficial because it improves nutrition by enabling milk consumption beyond infancy, providing a selective advantage in certain populations.
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