Transcription
Harry Potter Genetics
Genetics Review Chromosomes are found in the nucleus Each human has 46 chromosomes (23 pairs) In each pair, one chromosome comes from the mother andone chromosome comes from the father
Genetics Review The chromosomes are made of DNA Genes are small sections of DNA Each gene controls a trait (eye color, thumb shape,etc.)
Genetics Vocabulary Trait: The way an organism looks or behaves Alleles: different forms of the same trait Dominant Trait: The stronger trait/the one that willbe shown if the organism carries both alleles Recessive Trait: The weaker trait/the one that willbe hidden if the organism carries both alleles Homozygous: Both alleles are the same Heterozygous: Both alleles are different Genotype: The genetic code (the allele pair that theorganism carries) Phenotype: The physical, observable trait based onthe genotype
Genetics Review For each trait, a child inherits TWO possibilities One allele comes from the mother and one allelecomes from the father So we have two alleles for each trait The alleles in a pair can be the same (homozygous) The alleles in a pair can be different (heterozygous)homozygoushomozygousheterozygous
Genetics Review Alleles can be dominant or recessive Example: Straight thumb (S) dominant,curved thumb (s) recessive Possibilities: Homozygous Dominant (SS) – there areonly dominant alleles, so the child willhave straight thumbs Homozygous Recessive (ss) – there areonly recessive alleles, so the child willhave curved thumbs Heterozygous (Ss) – the dominant allele isstronger, so the child will have straightthumbsSSssSs
The Harry Potter Universe Wizards and witches have magical abilities Muggles do not have magical abilities
The Harry Potter Universe QUESTION: Is the “magic allele” dominantor recessive? Discuss the following information withyour partner and use it to decide if magicalability is dominant or recessive. Harry’s parents were both magic Ron’s parents are both magic – and all ofhis brothers and sisters are witches andwizards, too. Both of Hermione’s parents are Muggles,but she inherited magical abilities.
The Harry Potter Universe The Muggle (M) allele is DOMINANT The Magic (m) allele is RECESSIVE Harry’s grandparents were both heterozygous (Mm) Harry’s mom Lily is Magic Harry’s aunt Petunia is a Muggle What combinations are possible to make Lily & Petunia?
The Potter AncestorsHarry’s Grandmother(Mm)Muggle Muggle Muggle(MM)(Mm)(mM)75% chance ofbeing MuggleHarry’s Grandfather(Mm)Magic(mm)25% chance ofbeing Magic
The Potter FamilyJames Potter(mm)Magic(mm)Magic(mm)100% chance of being MagicLily Potter(mm)Magic(mm)Magic(mm)
The Dursley FamilyAunt Petunia Uncle Vernon(MM)(Mm)Muggle Muggle(MM)(MM)Muggle Muggle(mM)(mM)100% chance of being Muggle
The Weasley FamilyMr. Weasley(mm)Magic(mm)Magic(mm)Mrs. Weasley(mm)Magic(mm)Magic(mm)100% chance of being Magic
The Granger FamilyHermione’s parentsare both Muggles but Hermione is magic!(Some people question how Muggle parents canhave a Magic child. What can we predict about thegenotype of Hermione’s parents?)
The Granger FamilyMrs. Granger(Mm)Muggle(MM)Muggle(Mm)Mr. Granger(Mm)Muggle(mM)Hermione had a 25%chance of being MagicMagic(mm)
Punnett Squares Punnett squares are a mathematical way to predictthe possible offspring from any two parents. They are set up like this: One parent’s alleles along the top One parent’s alleles along the left sideParent 2Parent 1
Fill in the parent alleles Hermione’s dad: Mm Hermione’s mom: MmMmMm
Fill in the squares Pull each allele down or across, filling both squares in itsrow/column. You end up with 2 alleles in each square. The squares represent possible offspring.MmM MM MmmMm m m
Make Predictions Punnett Squares allow you to make predictions about thelikelihood of traits in offspring. 4 squares each square represents 25% (adds up to 100%) Add them up to get probabilities / make predictionsGenotype PredictionsMM: 1/4 25%Mm: 2/4 50%mm: 1/4 25%
Make Predictions Punnett Squares allow you to make predictions about thelikelihood of traits in offspring. 4 squares each square represents 25% (adds up to 100%) Add them up to get probabilities / make predictionsPhenotype PredictionsMuggle: 3/4 75%Magic: 1/4 25%
You Try! Ginny Weasley, who is Magic (mm) falls in love andmarries a Muggle who is (MM). Draw a Punnett Square topredict their offspring. What are the probabilities of each genotype (MM,Mm, mm)? What are the chances of having a Muggle child? A Magic child?
You Try! Percy Weasley who is Magic (mm) falls in love andmarries a Muggle who is (Mm). What are the probabilities of each genotype (MM,Mm, mm) What are the chances of having a Muggle child? A Magic child?
You Try! If Hermione and Ron (both Magic) have children, whatare the odds of having Muggle vs. Magic children? Usea Punnett Square to prove your answer.
Exit Ticket Write your answers on a sheet of binder paper Harry’s grandparents produced one Muggle child(Petunia) and one Magic child (Lily) We know Harry’s grandparents were Muggles. But howdo we know that their genotypes were both (Mm)? Isit possible that one or both could be (MM)? Draw 3 Punnett squares to show all possibilities(MM/MM), (Mm/MM), (Mm/Mm). Use the Punnett squares to explain why BOTH ofHarry’s grandparents HAD to be heterogenous (Mm).
The Harry Potter Universe QUESTION: Is the “magic allele” dominant or recessive? Discuss the following information with your partner and use it to decide if magical ability is dominant or recessive. Harry’s parents we
