Answer:
If both parents are healthy carriers of the gene that causes cystic fibrosis, then their concern is justified, since they have a 25% (1:4) chance of having a child with cystic fibrosis.
Explanation:
The gene that produces cystic fibrosis is called CFTR, and its inheritance pattern is autosomal recessive.
Both parents may have the gene and not manifest the disease - healthy carriers - since the condition of homozygosity is necessary for cystic fibrosis to appear. However, they are likely to have children who are healthy, healthy carriers or sick with cystic fibrosis:
Genotype of healthy carrier parents is N/cf, where N is the normal gene and Qf is the abnormal gene.
N/cf X N/cf
Alleles N cf
N N/N N/cf
cf N/cf cf/cf
The chances of having:
- Healthy child are 25%.
- Healthy carrier child are 50%.
- Child with cystic fibrosis are 25%.
In this case, the concern of both parents is justified, since the probability of having a child with cystic fibrosis is 1:4.
Lerarn more:
Cystic fibrosis inheritance brainly.com/question/6584627
