THE GENETICS OF
HARRY POTTER
Bell ringer: Why is it incredibly rare for a woman to have color-blindness?
HARRY POTTER
 Here’s the synopsis:
http://www.youtube.com/watch?v=18cZhqdxk3E
MENDELIAN GENETICS
 Some traits work simply, like Mendel predicted. They are either
dominant or recessive. Red hair is one of these.
 Red hair is recessive to all other hair colors.
THE WEASLEYS
 Red hair runs in the
Weasley family
THE WEASLEYS
 Harry’s father had brown hair and Harry’s mother had red hair.
What is Harry’s genotype? What are this father’s possible genotypes?
 Harry marries Ginny, a redhead. What are the possible genotypes
of their children?
HAGRID
 Hagrid is a giant. Giantism is a genetic trait,
however, it follows “incomplete dominance”
rules.
 Incomplete dominance is when alleles
blend. Neither one is completely dominant
over the other.
HAGRID
 A normal wizard is about 5 to 6 feet
tall. A giant is about 20 feet tall. Hagrid
on the other hand is about 12 feet tall.
What do you think his genoptype is?
 Hagrid’s brother is 20 feet tall. What
is his genotype? Can they be full
brothers?
HARRY’S EYES
 Harry’s eyes are often referred to in the books. Harry has green eyes.
His mother had green eyes and his father had hazel eyes.
 Eye color is a case of codominance. Blue eyes (i) are recessive to both
brown eyes (IB) and green (IG). When green and brown are both present,
hazel eyes result.
 Draw a punnett square to show the odds of Harry inheriting green
eyes.
HARRY’S EYES
 Using Harry’s genotype,
determine the genotypes of his
and Ginny’s children (Ginny has
brown eyes).
MAGICAL ABILITY
 In the magical world of Harry Potter, there are three kinds of
wizarding abilities: Strong, normal and weak (also called squibs).
 Magical ability is another incomplete trait. Those with normal
magical ability have the genotype Mm, while strong wizards have MM.
MR. FILCH
 Mr. Filch is the ground’s keeper at
Hogwarts. He has hardly any magical
ability. What is his genotype?
MAGICAL ABILITY
 Something else happens with magical ability: a silencing gene.
 Sometimes, a gene can be turned on and off. Another gene
controls whether a person will express the gene. In Harry Potter’s
world, some people have no magical ability because it is “silenced”.
HERMIONE
 Hermione is a witch born to two muggle
parents (people who have no magic). A gene
silenced her parents magical abilities, but not
hers because she has strong magical ability.
 What is Hermione’s genotype?
HERMIONE
 A gene for silencing magical ability is S. It is dominant. Anyone
who gets at least one S will be a muggle. Since Hermione is a witch,
what is her genotype?
HERMIONE
 Hermione’s possible genotype is MMss, indicating her strong
magical ability. What are possible genotypes of Hermione’s parents
who are Muggles without the ability?
HARRY POTTER
 Will Harry Potter and Ginny
Weasley have magical children?
 Harry’s cousin Dudley is a Muggle.
Is it possible for him to have magical
children? How?