Question

Which statement about cystic fibrosis is true?(1 point)
Responses

Carriers have an advantage over people who do not have the cystic fibrosis mutation.
Carriers have an advantage over people who do not have the cystic fibrosis mutation.
Cystic fibrosis is caused by a mutation in which a dominant allele replaces a recessive allele.
Cystic fibrosis is caused by a mutation in which a dominant allele replaces a recessive allele.
Cystic fibrosis is caused by a deletion of one codon in the DNA molecule.
Cystic fibrosis is caused by a deletion of one codon in the DNA molecule.
Cystic fibrosis affects a person’s ability to make normal red blood cells.

Answer 1

Cystic fibrosis is caused by a deletion of one codon in the DNA molecule.

Explanation: The most common CF mutation (ΔF508) is a three‑base (one codon) deletion that removes phenylalanine at position 508 of the CFTR protein, causing misfolding and defective chloride channels. The disease is autosomal recessive (not caused by a dominant allele replacing a recessive one) and does not affect red blood cell production.