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Harry Potter and the recessive characteristic. Wizards and muggles, its in the genes. chromosomes. gene. from father. from mother. Wizard or muggle?. Being a wizard or a muggle depends on genetics Characteristics are determined by genes that are found on chromosomes
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Harry Potter and the recessive characteristic Wizards and muggles, its in the genes
chromosomes gene from father from mother Wizard or muggle? • 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
Muggle allele (M) Wizard allele (m) Wizard or muggle? • 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
(mm) Wizard or muggle? The Malfoys Narcissa Malfoy Lucius Malfoy (mm) Draco Malfoy (mm) • The Malfoys are a “pure-blood” family • All their ancestors are wizards and therefore they only have mm
(mm) Wizard or muggle? The Potters 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
Wizard or muggle? The Weasleys • They are all pure-bloods so they all have mm and are wizards
Mm Mm mm 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 Hermione Granger (mm)
father mother Mm mm mm Wizard or muggle? • 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? 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?
children (mm) Wizard or muggle? • What if Ron and Hermione got together? • What sort of children would they have? Hermione (mm) Ron (mm)
Ron (mm) m m m Hermione (mm) m Wizard or muggle? • 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 • 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 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
children (?) 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)
Dudley (MM) M M m Ginny (mm) m Wizard or muggle? • Ginny will only be able to pass on ‘m’ • Dudley will only be able to pass on ‘M’ Mm Mm Mm Mm All children (100%) will be heterozygous and muggles!
M m M m Wizard or muggle? • 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) MM Mm ¾ (75% chance) would be a muggle ¼ (25% chance) would be a wizard Mrs Granger (Mm) Mm mm