Mutations in the CFTR gene cause cystic fibrosis (CF). The non-mutated allele of the gene can be obtained and then introduced into the lung cells of a person with CF using liposomes as a
vector. This treatment gives only short-term relief from the symptoms of CF.
Which of the following statements would be a correct explanation of this treatment?
1. Genes are unstable and break down over time in the cell.
2. Lung cells are constantly being replaced and new cells will have the faulty allele.
3. The non-mutated allele is recessive.