Question

genetics and heredity exam
possible
this is a two part question. use the information below to complete the punnett square.
in humans, dimples are dominant to no dimples.
a man and a woman both have dimples, but each has one parent without dimples.
part b
using the punnett square you completed in question 8 (part a), what is the probability of this couple having a child without dimples?
0%
25%
50%
100%

Explanation:

Step1: Define genotype notation

Let $D$ = dominant (dimples), $d$ = recessive (no dimples)

Step2: Determine parental genotypes

Each parent has a non-dimpled ($dd$) parent, so both are $Dd$.

Step3: Set up Punnett square

$$\begin{array}{c|cc} & D & d \\ \hline D & DD & Dd \\ d & Dd & dd \\ \end{array}$$

Step4: Calculate recessive probability

Count $dd$: 1 out of 4. Probability = $\frac{1}{4} = 25\%$

Answer:

25%