AP BIOLOGY HEREDITY ACTIVITY #7 NAME_____________________ DATE___________HOUR_____ FRUIT FLY PROBLEMS The letters and symbols used to represent genotypes in fruit flies are different that what is used to represent the genotypes of other organisms. For this lab you will need to use the following key when representing the genotypes of the flies involved in the crosses: KEY: + W Wild (red) type White eyes SE VG Sepia (brown) eyes Vestigial Wings PROBLEM A: CROSS BETWEEN FEMALE WITH WILD EYES AND A MALE WITH SEPIA EYES P Generation 2 Female Wild Eyes Male Sepia Eyes Genotype: Genotype: F1 Generation 2 Female Wild Eyes N = 5012 Genotype: Heredity Activity #7 page 1 Male Wild Eyes N = 4995 Genotype: F2 Generation Female Wild eyes N = 3676 Male Wild eyes N = 3748 Female Sepia eyes N = 1286 Male Sepia eyes N = 1272 1. Be sure that you provide the genotypes for all flies in the diagrams on previous page. 2. What mutation(s) were you following in this cross? (NOTE: Wild type is not a mutation. It is the normal condition in flies. The sex of the fly is not a mutation either.) _____________________________________________________________ 3. Examine the data for the F1 Generation and F2 Generation results. Make a hypothesis about the pattern of inheritance in this cross by answering the following questions: a. Is the cross autosomal or sex-linked?_______________________ Autosomal inheritance involves alleles on chromosomes other than the sex chromosomes. Sex-linked inheritance involves alleles found on the X chromosome. To answer this question you need to compare the number of males with a certain characteristics (wild eyes for example) with the number of females. If there is no significant difference between the numbers would you expect the pattern of inheritance to be autosomal or sex-linked? b. Is(are) the mutation(s) dominant or recessive?_________________ c. Is the cross monohybrid or dihybrid?_________________________ To answer this question you need to consider the number of mutations being tracked through the crosses. Heredity Activity #7 page 2 4. Using the key on page 1 and the answers to the previous question, construct a Punnett square to predict results of the P (parental) cross and the F1 cross. If you are sure that the cross is not sex-linked, you should combine the male and female numbers for the same phenotypes. P Cross: _______________ x _______________ (female genotype) (male genotype) Punnett Square: F1 Cross: _______________ x _______________ (female genotype) (male genotype) Punnett Square: 5. According to the Punnett square results, what are the expected phenotypic ratios of the F1 and F2 offspring? If you are sure your cross is not sex-linked, you should combine the male and female data for the same phenotypes. CROSS F1 F2 Heredity Activity #7 page 3 EXPECTED PHENOTYPIC RATIO 6. Look at the results of the F2 generation. How many total flies were produced in this cross? _____________________________________________________________ 7. Calculate the number of individuals you would expect to be produced from this cross. To do this you need to multiply the expected ratio (or percent) by the total number of flies produced in the cross. If you are sure that your cross is not sex-linked, you should combine the male and female data for the same phenotype. PHENOTYPES 8. Expected Ratio or Percent EXPECTED NUMBER Calculate the chi-square value for the F2 generation in the space below. You must show all work. 2 2 χ =∑ (o − e) e χ2 = ___________ Heredity Activity #7 page 4 9. Use the Chi-Square Distribution Table below to determine the percent probability that the observed variation is due to random chance alone. Degrees of freedom = _______________ % Probability = _________________ CHI-SQUARE DISTRIBUTION TABLE Accept Hypothesis Reject Hypothesis Probability (p) Degrees 0.95 0.90 0.80 0.70 0.50 of Freedom 1 0.004 0.02 0.06 0.15 0.46 2 0.10 0.21 0.45 0.71 1.39 3 0.35 0.58 1.01 1.42 2.37 4 0.71 1.06 1.65 2.20 3.36 5 1.14 1.61 2.34 3.00 4.35 10. 0.30 0.20 0.10 1.07 2.41 3.66 4.88 6.06 1.64 3.22 4.64 5.99 7.29 2.71 4.60 6.25 7.78 9.24 0.05 0.01 3.84 6.64 10.83 5.99 9.21 13.82 7.82 11.34 16.27 9.49 13.38 18.47 11.07 15.09 20.52 Was the deviation between the expected and observed data due to chance alone? _____________________________________________________________ How do you know?______________________________________________ _____________________________________________________________ 11. Based on the answer to the previous question, should you accept or reject your hypothesis regarding the pattern of inheritance for this cross? _____________________________________________________________ Explain._______________________________________________________ _____________________________________________________________ _____________________________________________________________ Heredity Activity #7 page 5 0.001 PROBLEM B: CROSS BETWEEN FEMALE WITH WILD EYES & VESTIGIAL WINGS AND A MALE WITH SEPIA EYES AND WILD WINGS P Generation 2 Female Wild Eyes Vestigial Wings Male Sepia Eyes Wild (normal) Wings Genotype: Genotype: F1 Generation 2 Female Wild Eyes Wild Wings N = 5003 Genotype: Male Wild Eyes Wild Wings N = 5080 Genotype: F2 Generation Female Wild eyes Wild wings N = 2805 Male Wild eyes Wild wings N = 2797 Female Sepia eyes Wild wings N = 974 Male Sepia eyes Wild wings N = 959 Female Wild eyes Vestigial wings N = 956 Male Wild eyes Vestigial wings N = 872 Female Sepia eyes Vestigial wings N = 337 Male Sepia eyes Vestigial wings N = 301 Heredity Activity #7 page 6 12. Be sure that you provide the genotypes for all flies in the diagrams on the previous page. 13. What mutation(s) were you following in this cross? (NOTE: Wild type is not a mutation. It is the normal condition in flies.) _____________________________________________________________ 14. 15. Examine the data you collected form your crosses (F1 Generation and F2 Generation results). Make a hypothesis about the pattern of inheritance in this cross by answering the following questions: a. Is the cross autosomal or sex-linked?_______________________ b. Is(are) the mutation(s) dominant or recessive?_________________ c. Is the cross monohybrid or dihybrid?_________________________ Using the key on page 1 and the answers to the previous question, construct a Punnett square to predict results of the P (parental) cross and the F1 cross. If you are sure that the cross is not sex-linked, you should combine the make and female numbers for the same phenotypes. P Cross: _______________ x _______________ (female genotype) (male genotype) Punnett Square: Heredity Activity #7 page 7 F1 Cross: _______________ x _______________ (female genotype) (male genotype) Punnett Square: 16. According to the Punnett square results, what are the expected phenotypic ratios of the F1 and F2 offspring? If you are sure your cross is not sex-linked, you should combine the male and female data for the same phenotypes. CROSS EXPECTED PHENOTYPIC RATIO F1 F2 17. Look at the results of the F2 generation. How many total flies were produced in this cross? _____________________________________________________________ Heredity Activity #7 page 8 18. Calculate the number of individuals you would expect to be produced from this cross. To do this you need to multiply the expected ratio (or percent) by the total number of flies produced in the cross. If you are sure that your cross is not sex-linked, you should combine the male and female data for the same phenotype. PHENOTYPES 19. Expected Ratio or Percent EXPECTED NUMBER Calculate the chi-square value for the F2 generation in the space below. You must show all work. 2 2 χ =∑ (o − e) e χ2 = ___________ Heredity Activity #7 page 9 20. Use the Chi-Square Distribution Table from question #9 to determine the percent probability that the observed variation is due to random chance alone. Degrees of freedom = _______________ % Probability = 21. _________________ Was the deviation between the expected and observed data due to chance alone? _____________________________________________________________ How do you know?______________________________________________ _____________________________________________________________ 22. Based on the answer to the previous question, should you accept or reject your hypothesis regarding the pattern of inheritance for this cross? _____________________________________________________________ Explain._______________________________________________________ _____________________________________________________________ _____________________________________________________________ PROBLEM C: CROSS BETWEEN FEMALE WITH WILD EYES AND A MALE WITH SEPIA EYES P Generation 2 Female White eyes Genotype: Heredity Activity #7 page 10 Male Wild eyes Genotype: F1 Generation 2 Female Wild eyes N = 5019 Genotype: Male White eyes N = 5008 Genotype: F2 Generation Female Wild eyes N = 2579 Male Wild eyes N = 2454 Female White eyes N = 2545 Male White eyes N = 2467 23. Be sure that you provide the genotypes for all flies in the diagrams on pages 10 and 11. 24. What mutation(s) were you following in this cross? (NOTE: Wild type is not a mutation. It is the normal condition in flies.) _____________________________________________________________ 25. Examine the data you collected form your crosses (F1 Generation and F2 Generation results). Make a hypothesis about the pattern of inheritance in this cross by answering the following questions: a. Is the cross autosomal or sex-linked?_______________________ b. Is(are) the mutation(s) dominant or recessive?_________________ c. Is the cross monohybrid or dihybrid?_________________________ Heredity Activity #7 page 11 26. Using the key below and the answers to the previous question, construct a Punnett square to predict results of the P (parental) cross and the F1 cross. If you are sure that the cross is not sex-linked, you should combine the make and female numbers for the same phenotypes. P Cross: _______________ x _______________ (female genotype) (male genotype) Punnett Square: F1 Cross: _______________ x _______________ (female genotype) (male genotype) Punnett Square: Heredity Activity #7 page 12 27. According to the Punnett square results, what are the expected phenotypic ratios of the F1 and F2 offspring? If you are sure your cross is not sex-linked, you should combine the male and female data for the same phenotypes. CROSS EXPECTED PHENOTYPIC RATIO F1 F2 28. Look at the results of the F2 generation. How many total flies were produced in this cross? _____________________________________________________________ 29. Calculate the number of individuals you would expect to be produced from this cross. To do this you need to multiply the expected ratio (or percent) by the total number of flies produced in the cross. If you are sure that your cross is not sex-linked, you should combine the male and female data for the same phenotype. PHENOTYPES Heredity Activity #7 page 13 Expected Ratio or Percent EXPECTED NUMBER 30. Calculate the chi-square value for the F2 generation in the space below. You must show all work. χ2 = ___________ 31. Use the Chi-Square Distribution Table from question #9 to determine the percent probability that the observed variation is due to random chance alone. Degrees of freedom = _______________ % Probability = 32. _________________ Was the deviation between the expected and observed data due to chance alone? _____________________________________________________________ How do you know?______________________________________________ _____________________________________________________________ 33. Based on the answer to the previous question, should you accept or reject your hypothesis regarding the pattern of inheritance for this cross? _____________________________________________________________ Explain._______________________________________________________ _____________________________________________________________ _____________________________________________________________ Heredity Activity #7 page 14
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