Punnett Square Practice Worksheet #2
Name:
Period:
Directions: Complete numbers 1 & 2 below. THEN do ONE for each of the following sets:
# 3 OR 4; 6 OR 7;
5 OR 8
1) For each of the genotypes (AA, Aa or aa) below determine what the phenotype would be.
Example: Purple flowers are dominant to white flowers.
PP __PURPLE__
Pp PURPLE
pp WHITE .
Hairy knuckles are dominant to non-hairy knuckles in humans.
HH_____________
Hh ___________
hh _________________
Bobtails in cats are recessive. Normal tails are dominant.
TT _____________
Tt _________
tt _____________
No-cleft chin is dominant. Cleft chin is recessive.
CC ___________
Cc __________
cc _____________
2) For each of the following write whether it is homozygous dominant, heterozygous or homozygous recessive.
AA
Ff
GG
Pp
Aa
gg
Ii
tt
Use the following information for questions 3 & 4:
In dogs, the gene for fur color has two alleles. The dominant allele (F) codes for grey fur and the
recessive allele (f) codes for black fur.
3) The female dog is heterozygous for grey fur and the male dog has black fur. Figure out the phenotypes and genotypes
of their possible puppies by using a Punnett Square.
4) Both dogs are heterozygous for grey fur. Figure out the phenotypes and genotypes of their possible puppies by using a
Punnett Square.
5) Achondroplasia is said to be an “autosomal” dominant trait that causes extreme dwarfism in humans. How is it
possible that two individuals with achondroplasia can produce a normal child? What is the chance of this happening?
Use the following for questions 6 & 7:
Having a widow’s peak like Wentworth Miller is dominant.
Not having a widow’s peak, like Rihanna, is recessive.
6) If Wentworth Miller is heterozygous for his widow’s peak, and he and Rihanna had children, what are the possible
phenotypes and genotypes of their children?
7) Look at the phenotypes of Beyonce and Jay Z. If these two had children, could they have children with a widow’s
peak? Why or why not? Use a Punnett Square to explain your answer.
8) A left handed woman marries a right handed man. After 5 years of marriage they have a baby girl that is also left
handed. The dad is distraught and believes the child is not his. If being left handed is a recessive trait (right handed is
dominant), is the dad valid in his conclusion (is it possible for them to produce a left handed child)? Use a punnett
square to validate your answer.