Year 10 Genetics Worksheet:Dominant and Recessive Inheritance
All of these questions relate to the dimples some people get in their cheeks when they
smile. Cheek dimples (D) are dominant to no dimples (d).
1) What are the possible genotypes of a person with:
a. No dimples
b. Dimples.
2) What will be the phenotypes (ie.dimples or no dimples) of the following?
a. DD
b. Dd
c. dd
3) Use the punnett squares to work out the most probable distribution of the offspring of the
following crosses:
a. DD X Dd
b. DD X dd
c. DD X DD
d. Dd X Dd
e. dd X dd
f.
Dd X dd
4) Which of the above crosses from question 3 could produce a non-dimpled person? (Use
the letters)
5) Which of the above crosses from question 3 could produce offspring of more than one
genotype? (Use the letters)
6) Which of the above crosses from question 3 shows that if two parents have dimples,
their children may not have dimples? Explain
7) If neither parent has dimples, can any of their children have dimples? Explain by
referring to the punnett squares in question 3.