Cystic fibrosis is a recessive trait. Imagine that your friend, Roger, has cystic fibrosis but that his parent

Question

a. This information is insufficient to allow me to conclude anything about Roger's parents' DNA.
b. This information is insufficient to allow me to conclude anything about the cystic fibrosis alleles in Roger's DNA.
c. Roger is heterozygous (2 different alleles) and his parents are homozygous (two identical alleles) at the cystic fibrosis locus.
d. Roger is homozygous and his parents are heterozygous at the cystic fibrosis locus.

Answer 1

Your question is incomplete, but if Roger has CF, then he is either homozygous for a CF mutation or he is a double heterozygote, that is, he has two different gene mutations, each of which cause CF.
His parents are any of the following:

1. Heterozygous - both are carriers of a gene mutation, either for the same, or different mutations.

2. One is homozygous or double heterozygous, and has lived long enough to have children. Generally CF sufferers are sterile due to incomplete formation of the vas deferens in males and fallopian tubes in females, but assisted reproduction allows either sperm or egg harvesting to bypass these malformations. The other is either heterozygous, homozygous or double heterozygous.
.
Hope your answer is here.

Answer 2

his parent..... and a adn b are the same...

i can tell you that c is incorrect already