Modeling Sex-Linked Inheritance part 123
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School
Brookline High**We aren't endorsed by this school
Course
BIOLOGY AP BIOLOGY
Subject
Biology
Date
Dec 20, 2024
Pages
2
Uploaded by SargentWorld15909
Part I: Establishing the Genotypes and Phenotypes of the ParentsXX parentXY parentGenotypeXBXbXBYPhenotype (DMD? noDMD?)normal dystrophin proteinNo DNDnormal dystrophin proteinNo DNDPart II: Simulating Meiosis I and II1.One pair of students should simulate meiosis I and II for XX, and the other pair ofstudents should simulate meiosis I and II for XY. You need to actually line up, move,and split the chromosomes, to simulate what would happen in meiosis I and II.2.Each pair of students should have formed 4 gametes.3.In this simulation, how many chromosomes are in each gamete? ___1___4.If you were modeling actual human meiosis I and II, how many chromosomeswould be in each gamete? __23____5.What percentage of the gametes from the XY person have the XBallele? __50__6.What percentage of the gametes from the XY person have the Xballele? ___0__7.What percentage of the gametes from the XY person have the Y chromosome? _5__8.What percentage of the gametes from the XX person have the XBallele? __50_9.What percentage of the gametes from the XX person have the Xballele? __50__10. What percentage of the gametes from the XX person have the Y chromosome? __0__Part III: Simulating Fertilization11. On one side of the table, place the gametes from the XX person. On the otherside of the table, place your gametes from the XY person.12.Without looking, randomly choose a gamete from the XX person, and thenrandomly choose a gamete from the XY person. What is the genotype of the zygoteyou just formed? XBXb13.Put each single chromosome back into the correct pile of gametes, so that eachpile still has 4 total gametes.14.Repeat steps 12 and 13 fifteen more times. Record each of your 16 offspring(zygotes) in the chart below.1
XBXBXBXbXbXbXBYXbY# of zygotes43053DMD?nonoyesnoyes15.Were any of the above zygotesimpossibleto form, given the genotypes of theparents? __yes___ Explain why or why not. _____There could never be an XbXbbecause there is only 1 parent that creates the allele → Xb16. With what parental genotypes could an XX individual inherit DMD? ___XbXB__ x__XbXB___17. Explain why DMD is more common in XY individuals, as compared to XXindividuals. __In XY individuals there only needs to be 1 Xbgiven by the XX parent togive DMD. In an example like the one above. If there is an XBXb cross with XBY, therewould be a 25% chance of an XY with DMD but never an XX offspring with DMD.2