1. Harry Potter and the recessive characteristic
Wizards and muggles, its in the genes

2. Wizard or muggle? chromosomes gene from mother from father
Being a wizard or a muggle depends on genetics
Characteristics are determined by genes that are found on chromosomes
Individuals have two sets of chromosomes, one set from the mother the other set from the father
Therefore for a particular gene each individual will have two copies, one from the mother and one from the father

3. Wizard or muggle?
Wizard allele (m)
Muggle allele (M)
Genes can have different forms called alleles, eg wizard allele or muggle allele
The muggle allele is assigned the letter ‘M’ and the wizard allele is assigned ‘m’
It is this combination that determines whether you are a wizard or a muggle
To be a wizard you must have mm
A muggle can have MM or Mm

4. The Malfoys Wizard or muggle? Narcissa Malfoy Lucius Malfoy (mm)
Draco Malfoy
(mm)
(mm)
The Malfoys are a “pure-blood” family
All their ancestors are wizards and therefore they only have mm

5. The Potters Wizard or muggle? James Potter (mm) Lily Potter (mm)
Harry Potter
Both Harry’s parents had magical ability, so they must both have been mm
Harry will have received an ‘m’ from each parent

6. The Weasleys Wizard or muggle?
They are all pure-bloods so they all have mm and are wizards

7. Wizard or muggle?
Hermione is a witch with powerful magical abilities but she does not come from a pure-blood family
Neither of her parents had magical abilities
What were her parents’ genes?
They must have both been Mm Mm mm
Hermione Granger (mm)

8. Wizard or muggle? Mm mm Tom riddle is “half-blood”
His mother had magical abilities but his father was a muggle
What combination of alleles must Tom’s father have? Mm mm
father
mother
Tom Riddle (mm)

9. Wizard or muggle? Filch is a “squib”
Both his parents were wizards and therefore mm
This means that Filch must also be mm but he has no magical abilities
Why is this so?
One possibility is that he has a mutation that has resulted in the genes not working
Another possibility is that some environmental factor has affected his wizard genes working
Or is his father really his father? Hmmm…
Argus Filch (mm)
Wizard or not?

10. Wizard or muggle? What if Ron and Hermione got together?
What sort of children would they have?
Hermione (mm)
Ron (mm)
children (mm)

11. Wizard or muggle? m m mm mm mm mm
We can use a punnet square to predict the characteristics of the next generation (offspring)
The alleles of each parent are placed on the sides
Ron (mm)
Hermione (mm) m
All the different combinations are worked out
Remember only one allele is passed on, but it is totally random and each has the same chance m mm mm mm mm
All children must be mm!

12. Wizard or muggle? Some terminology
GENOTYPE is the combination of alleles eg Mm or mm or MM
PHENOTYPE is the characteristic that we observe eg muggle or wizard
HOMOZYGOUS is when both the alleles are the same eg MM or mm
HETEROZYGOUS is when the two alleles are different eg Mm
PURE-BREED is another word for homozygous
HYBRID is another word for heterozygous
DOMINANT is the trait you see when either type of allele is present- muggle
RECESSIVE is the trait you see only when both alleles are the same type- wizard

13. Wizard or muggle?
What if Ginny and Dudley got together? What would their children be like?
Dudley is related to Harry but is definitely not a wizard. He is homozygous.
Ginny Weasley (mm)
Dudley Dursley (MM)
children (?)

14. All children (100%) will be heterozygous and muggles!
Wizard or muggle?
Ginny will only be able to pass on ‘m’
Dudley will only be able to pass on ‘M’
Dudley (MM)
Ginny (mm) M m Mm Mm Mm Mm
All children (100%) will be heterozygous and muggles!

15. Wizard or muggle? M m M m MM Mm Mm mm
What wizarding alleles would you expect Hermione’s brothers and sisters to have?
Remember Hermione is a “muggle-born”. What must her parents have been?
They both must have been heterozygous.
Mr Granger (Mm) M m M m MM Mm
¾ (75% chance) would be a muggle
¼ (25% chance) would be a wizard
Mrs Granger (Mm) Mm mm