Question

John and Sarah had a child born with cystic fibrosis, a genetic disease. Both John and Sarah were normal, showing no signs of this disorder. How is it possible for them to have a child with this disease?

a. Cystic fibrosis must be a dominant trait disorder hidden in both parents' genotype, but not showing in the phenotype, that could be passed on to offspring.

b.Cystic fibrosis must be a recessive trait disorder hidden in both parents’ genotype, but not showing in the phenotype, that could be passed on to offspring.

c. Cystic fibrosis must be a dominant trait disorder hidden in one parents’ genotype, but not showing in the phenotype, that could be passed on to offspring.

d.Cystic fibrosis must be a recessive trait disorder hidden in one parents’ genotype, but not showing in the phenotype, that could be passed on to offspring

Answer 1

it is b

Step-by-step explanation:

reccesive doesn show in the phenotype because its covered by the dominant trait so the parents were fine but it is both parents so that the kid has an rr and not Rr or RR so that the reccesive trait would be covered by the dominant in the phenotype so B

Answer 2

B

My logic:

I did a whole project on genetics and i love genetics. I know for a fact this is the correct answer because i had it 2 years ago on a test and got it correct. On the off chance im wrong, it has been 2 years and i might have mixed my facts up.

Hope this helps!