Question

A male and a female are each heterozygous for both cystic fibrosis (CF) and phenylketonuria (PKU). Both conditions are autosomal recessive and the alleles assort independently.^

Need detail explanation for the question C, and I'm not certain, if the answer is correct.<--------------------------------------------

I'm pretty sure that answers for A and B are correct.

A.What proportions of the children of this couple will have neither condition?
My answer 9/16

B. What proportion of the children will have either PKU or CF?

My answer is 6/16

C.What proportion of the children will be carriers of one or both conditions?

Both cycstic fibrosis and Phenylketonuria = ccpp = 1/4 * 1/4 = 1/16<-----Is this correct???? And could anyone explain how this work?

Answer 1

Both conditions are autosomal recessive, and they assort independently.
Cc Pp x Cc Pp

Cc x Cc
CC-1/4
Cc -2/4
cc ---1/4


Pp x Pp
PP-1/4
Pp-2/4
pp----1/4

A: What proportion of the children of this couple will have neither condition?

3/4 x3/4 = 9/16   = 0.5625

B: What proportion of the children will have either (PKU) or (CF) but not both?

3/16 + 3/16 = 6/16   = 0.375

C.What proportion of the children will be carriers of one or both conditions?

1/4 x 1/4 = 1/16