Question

question 8 of 11
if a recessive genetic disorder is represented by allele \d\ and two carriers (dd) have a child, what is the probability their child will inherit the disorder?
0%
25%
50%
100%

Explanation:

Step1: Set up Punnett - square

We have two parents with genotype Dd. The possible gametes from each parent are D and d.

Step2: Fill in Punnett - square

	D	d
d	Dd	dd

Step3: Determine probability

There are 4 possible genotypes for the offspring: DD, Dd, Dd, dd. The recessive disorder is expressed in the dd genotype. So the probability of getting a dd offspring is $\frac{1}{4}$ or 25%.

Answer:

B. 25%