LS7B Week 2 Lab Worksheet Name Part 1 Modeling Meiosis Draw the chromosomes as they would appear in each cell shown in the diagram below Include Gene A and Gene D in your drawings and be sure to designate which genes alleles are present in each cell Double check that the alignment for the chromosomes is accurate during metaphase I and metaphase II assume no crossing over Gene Durian Yellow chromosomes alleles labeled D and d Gene Apple Red chromosomes alleles labeled A and a 1 Explain Mendel s principles of segregation and independent assortment 2 Assuming no crossing over does segregation of alleles occur in meiosis I or II Explain your reasoning 3 Assuming no crossing over does assortment of genes take place in meiosis I or II Explain your reasoning Part II Modelling Non Disjunction In the following cells model what would result if the larger chromosome with the A and a alleles experienced NDJ in Meiosis I Assume no crossing over Modelling Non Disjunction In the following cells model what would result if the larger chromosome with the A and a alleles experienced NDJ in Meiosis II Assume no crossing over 1 How many different allele combinations in the gametes are produced when meiosis occurs without NDJ compared to when NDJ occurs in the larger chromosome the smaller chromosome proceeds through meiosis correctly in Meiosis I and Meiosis II Part 3 Using Punnett squares determine the phenotypes of offspring that the following parents could produce For some situations there could be more than one genotype for at least one of the parents In these cases be sure to include Punnett squares for all possibilities 1 An autosomal recessive trait with an unaffected XX parent and an affected XY parent 2 An autosomal dominant trait with an affected XX parent and an unaffected XY parent 3 An X linked recessive trait with an unaffected XX parent and an affected XY parent 4 An X linked dominant trait with an unaffected XX parent and an affected XY parent