1. The protagonist
Harry is the son of Lily and James Potter. Lily Potter was magical although she had two parents without any magical ability—i.e., Muggles. Lily's sister, Petunia, did not inherit the magical ability.
Predict Lily’s family geno/phenotypes
Harry & parents, too

2. The protagonist Lily’s family Harry’s parents
Both express homozygous phenotype, therefore only homozygous recessive offspring possible
Petunia
Lily

3. The Dursley side of the family
Dudley Dursley is Harry's cousin, the only son of his maternal aunt, Petunia, who is married to Vernon Dursely, No Dursley has ever had magical powers.
Can Dudley pass on the magic? Predict via a Punnett

4. The Dursley side of the family
Can Dudley pass on the magic?
mom
dad
Dudley

5. Harry’s bestie Ron
Ron Weasley is Harry's best friend. Ron and his many siblings have red hair, a recessive trait.
Infer his parents pheno & genotype for hair color.

6. Girls rule
Hermione is one of Harry's best friends and is a powerful witch. She has parents who are Muggles who do not possess magical ability.
Hermione’s parents genotypes?

7. Little Potters Harry marries Ginny Weasley who has red hair.
What are possible genotypes & phenotypes of their children’s hair color?

8. About Filch
Mr. Filch is the caretaker of the Hogwarts School of Witchcraft and Wizardry. He had one parent with magical ability but has only weak magical ability himself – a squib.
What’s this allele relationship?