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

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

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

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

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

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

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)

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)

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?

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

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!

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

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 (?)

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!

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