Harry Potter Genetics
1. Ron Weasley has red hair. What is his
genotype?
bb
2. Harry Potter has brown hair. What are
his possible genotypes?
BB or Bb
3. If a wizard is heterozygous for hair
color, what is his genotype?
Bb
4. What is his phenotype?
Brown hair
5. Harry Potter’s dad James is
homozygous for brown hair. What
is his genotype?
BB
6. Harry, Ron, and Hermione have magical
abilities. What is their genotype?
mm
7. A man is heterozygous for magical ability.
What is his genotype?
Mm
8. Would he be a muggle or a wizard?
muggle
Molly and Arthur Weasley both have red hair.
9. What are their genotypes?
Molly: bb
Arthur: bb
Molly and Arthur Weasley both have red hair.
bb
bb
10. Set up and fill in a Punnett square.
b
b
b bb
bb
b bb
bb
Molly and Arthur Weasley both have red hair.
11. What is the probability their children will
have red hair?
Probability of red hair (bb):
b
b bb
b
bb
b bb
bb
4 out of 4 or 100%
Harry Potter’s mom Lily had red hair.
His dad James was homozygous for brown hair.
12. What are their genotypes?
Lily: bb
James: BB
Harry Potter’s mom Lily had red hair . bb
His dad James was homozygous for brown hair. BB
13. What was the probability that Harry would have brown hair?
Harry Potter’s mom Lily had red hair . bb
His dad James was homozygous for brown hair. BB
13. What was the probability that Harry would have brown hair?
B
B
b Bb
Bb
b Bb
Bb
Probability of brown
hair (BB or Bb):
4 out of 4 or 100%
14. Harry Potter (genotype Bb) marries Ginny Weasley, who has
red hair (bb). What is the probability their children will have
red hair?
14. Harry Potter (genotype Bb) marries Ginny Weasley, who has
red hair (bb). What is the probability their children will have
red hair?
B
b Bb
b
bb
b Bb
bb
Probability of red hair
(bb):
2 out of 4 or 50%
Hermione has brown hair. She marries Ron, who has red hair.
They have two children, who both have red hair.
15. What must Hermione’s genotype be?
Hermione has brown hair. She marries Ron, who has red hair.
They have two children, who both have red hair.
15. What must Hermione’s genotype be?
b
B Bb
b bb
b
Bb
bb
Ron (red hair): bb
Hermione (brown hair): BB or Bb
Children (red hair): bb
For the children to have red
hair, Hermione must be
heterozygous (Bb).
Hermione has brown hair. She marries Ron, who has red hair.
They have two children, who both have red hair.
15. What must Hermione’s genotype be?
b
b
B Bb
Bb
B Bb
Bb
If Hermione were homozygous
for brown hair (BB), all of their
children would have the
genotype Bb and would have
brown hair.
16. Hermione is a witch. Her parents are muggles. What must
Hermione’s parents’ genotypes be?
16. Hermione is a witch. Her parents are muggles. What must
Hermione’s parents’ genotypes be?
Hermione’s genotype must
be mm because she has
magical abilities.
M
m
M MM Mm
m Mm mm
The only way she could have
the genotype mm is if both
of her parents were
heterozygous (Mm).
17. If Hermione had a brother, what is the probability he would
be a muggle?
M
m
M MM Mm
m Mm mm
17. If Hermione had a brother, what is the probability he would
be a muggle?
M
m
M MM Mm
m Mm mm
Genotypes for muggle:
MM or Mm
17. If Hermione had a brother, what is the probability he would
be a muggle?
M
m
M MM Mm
m Mm mm
Probability of being a muggle:
MM or Mm
3 out of 4 or 75%