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MENDELLIAN GENETICS LAB Click on a box to begin. SCIENCE 10 LIFE SCIENCES: GENETICS PART A Analyzing results PART B Predicting results PART C Explaining.

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Presentation on theme: "MENDELLIAN GENETICS LAB Click on a box to begin. SCIENCE 10 LIFE SCIENCES: GENETICS PART A Analyzing results PART B Predicting results PART C Explaining."— Presentation transcript:

1 MENDELLIAN GENETICS LAB Click on a box to begin. SCIENCE 10 LIFE SCIENCES: GENETICS PART A Analyzing results PART B Predicting results PART C Explaining results PART D Experimental design Genome British Columbia, 2004

2 PART A: COMPLETE DOMINANCE INTRODUCTION: Youre back in 1865 and Gregor Mendel is getting ready to publish his results. Being a good scientist, he wants to check that his results are repeatable. Youve just been hired by Mendel to study the heredity of two traits: 1.seed color: green or yellow 2.seed shape: smooth or wrinkled

3 yellow, winkled green, smooth yellow, smooth OBJECTIVE: Mendel gives you three plants that produce the following seeds: He asks you to breed new plants to determine the genotypes of these plants.

4 PROCEDURE: Click on the plants that you would like to cross. self-fertilize self-fertilize self-fertilize cross-fertilize cross-fertilize cross-fertilize Click here when you have finished collecting all your data.

5 You need to select the plants that you want to cross to see the data. Click anywhere on this screen to go back.

6 You need to select the plants that you want to cross to see the data. Click anywhere on this screen to go back.

7 DATA: Click anywhere on this screen to go back. Remember to record this data in your data table. self-fertilized

8 Click anywhere on this screen to continue.

9 DATA: self-fertilized Click anywhere on this screen to go back. Remember to record this data in your data table.

10 Click anywhere on this screen to continue.

11 DATA: self-fertilized Click anywhere on this screen to go back. Remember to record this data in your data table.

12 Click anywhere on this screen to continue.

13 DATA: Click anywhere on this screen to go back. Remember to record this data in your data table. cross-fertilized

14 Click anywhere on this screen to continue.

15 DATA: Click anywhere on this screen to go back. Remember to record this data in your data table. cross-fertilized

16 Click anywhere on this screen to continue.

17 DATA: Click anywhere on this screen to go back. Remember to record this data in your data table. cross-fertilized

18 Click anywhere on this screen to continue.

19 What is the dominant allele for seed color? ANALYSIS: YELLOW GREEN

20 What is the dominant allele for seed color? ANALYSIS: YELLOW GREEN Yellow

21 What is the dominant allele for seed color? ANALYSIS: YELLOW GREEN Yellow It is the more common color. A dominant allele always covers a recessive allele.

22 What is the recessive allele for seed shape? ANALYSIS: SMOOTH WRINKLED

23 What is the recessive allele for seed shape? ANALYSIS: SMOOTH Wrinkled WRINKLED

24 What is the recessive allele for seed shape? ANALYSIS: SMOOTH Wrinkled It is the less common shape. A recessive allele is always covered by a dominant allele. WRINKLED

25 CONCLUSION: If we use Y for yellow color & S for smooth shape. What is the genotype of the plant that produces the yellow, wrinkled seeds? A.YYSSC.YySs B.YYssD.Yyss

26 CONCLUSION: If we use Y for yellow color & S for smooth shape. What is the genotype of the plant that produces the yellow, wrinkled seeds? A.YYSSC.YySs B.YYssD.Yyss Hint:A self-fertilized parent that produces offspring with the identical traits must be homozygous for both traits.

27 CONCLUSION: If we use Y for yellow color & S for smooth shape. What is the genotype of the plant that produces the yellow, wrinkled seeds? A.YYSSC.YySs B.YYssD.Yyss Hint:A self-fertilized parent that produces offspring with the identical traits must be homozygous for both traits. B. YYss

28 Ys YYss Ys YYss Ys YYss Ys YYss self-fertilized

29 CONCLUSION: If we use Y for yellow color & S for smooth shape. What is the genotype of the plant that produces the green, smooth seeds? A.YySSC.yySS B.YySsD.yySs

30 CONCLUSION: If we use Y for yellow color & S for smooth shape. What is the genotype of the plant that produces the green, smooth seeds? A.YySSC.yySS B.YySsD.yySs C. yySS

31 yS yySS yS yySS yS yySS yS yySS self-fertilized

32 CONCLUSION: If we use Y for yellow color & S for smooth shape. What is the genotype of the plant that produces the yellow, smooth seeds? A.YySsC.YYSs B.YySSD.YYSS

33 CONCLUSION: If we use Y for yellow color & S for smooth shape. What is the genotype of the plant that produces the yellow, smooth seeds? A.YySsC.YYSs B.YySSD.YYSS A. YySs

34 YSYsySys YS YYSSYYSsYySSYySs Ys YYSsYYssYySsYyss yS YySSYySsyySSyySs ys YySsYyssyySsyyss self-fertilized

35 PART B: COMPLETE DOMINANCE (cont.) INTRODUCTION: Before giving Mendel your results from Part A, you decide to verify your results by self- fertilizing certain F 1 offspring. OBJECTIVES: For the following crosses, predict the genotypes and phenotype ratios for the F 2 offspring.

36 self-fertilized ? YYssyySS ? yySSYySs self-fertilized YySsYYss self-fertilized ? For each cross, predict the genotype and phenotype ratio, then click on that box to see the expected results. PROCEDURE:

37 YSYsySys YS YYSSYYSsYySSYySs Ys YYSsYYssYySsYyss yS YySSYySsyySSyySs ys YySsYyssyySsyyss YySs Phenotype ratio: RESULTS:

38 YSYsySys YS YYSSYYSsYySSYySs Ys YYSsYYssYySsYyss yS YySSYySsyySSyySs ys YySsYyssyySsyyss YySs Phenotype ratio: 9 yellow, smooth 3 yellow, wrinkled 3 green, smooth 1 green, wrinkled RESULTS:

39 yS yySS yS yySS yS yySS yS yySS If homozygous, then phenotype ratio: RESULTS: yySS

40 yS yySS yS yySS yS yySS yS yySS If homozygous, then phenotype ratio: all green, smooth RESULTS: yySS

41 yS yySS yS yySS yS yySS yS yySS If homozygous, then phenotype ratio: all green, smooth or If heterozygous, then phenotype ratio: RESULTS: yySS

42 yS ys yS yySS yySs yS yySS yySs ys yySs yyss ys yySs yyss Phenotype ratio: RESULTS: yySs

43 yS ys yS yySS yySs yS yySS yySs ys yySs yyss ys yySs yyss Phenotype ratio: 12 green, smooth 4 green, wrinkled RESULTS: yySs

44 Ys YYss Ys YYss Ys YYss Ys YYss If homozygous, then phenotype ratio: RESULTS:YYss

45 Ys YYss Ys YYss Ys YYss Ys YYss If homozygous, then phenotype ratio: all yellow, wrinkled RESULTS:YYss

46 Ys YYss Ys YYss Ys YYss Ys YYss If homozygous, then phenotype ratio: all yellow, wrinkled or If heterozygous, then phenotype ratio: RESULTS:YYss

47 Ys ys Ys YYss Ys YYss ys YYss yyss ys YYss yyss Phenotype ratio: RESULTS:Yyss

48 Ys ys Ys YYss Ys YYss ys YYss yyss ys YYss yyss Phenotype ratio: 12 yellow, wrinkled 4 green, wrinkled RESULTS:Yyss

49 PART C: INCOMPLETE DOMINANCE INTRODUCTION: Mendel is impressed with your intelligence and hard work, so he decides to gives you another project to work on. OBJECTIVES: Given the following data, explain the results.

50 self-fertilized DATA:

51 ANALYSIS: Phenotype ratios: F 1 F 2

52 ANALYSIS: Phenotype ratios: F 1 all medium F 2

53 ANALYSIS: Phenotype ratios: F 1 all medium F 2 1 long : 2 medium : 1 short

54 ANALYSIS: Phenotype ratios: F 1 all medium F 2 1 long : 2 medium : 1 short Intermediate phenotype and phenotype ratios indicates incomplete dominance.

55 If we use L for long size & l for short size. Note: There is insufficient information to determine which allele is more dominant, so long size was arbitrarily chosen as dominant. F1F1

56 If we use L for long size & l for short size. Note: There is insufficient information to determine which allele is more dominant, so long size was arbitrarily chosen as dominant. F1F1 LL l l L l Phenotype ratio:

57 If we use L for long size & l for short size. Note: There is insufficient information to determine which allele is more dominant, so long size was arbitrarily chosen as dominant. F1F1 LL l LlLlLlLl l LlLlLlLl L l Phenotype ratio:

58 If we use L for long size & l for short size. Note: There is insufficient information to determine which allele is more dominant, so long size was arbitrarily chosen as dominant. F1F1 LL l LlLlLlLl l LlLlLlLl LLl Phenotype ratio: all medium

59 F2F2 Phenotype ratio:

60 F2F2 Ll L l Phenotype ratio: LlLlLlLl

61 F2F2 Ll L LLLlLl l LlLll Phenotype ratio: LlLlLlLl

62 F2F2 Ll L LLLlLl l LlLll Phenotype ratio: 1 long 2 medium 1 short LlLlLlLl

63 PART D: CODOMINANCE INTRODUCTION: Mendels results were not well received by other scientists. With his extensive experience in growing pea plants, he pursues a career in farming. He decides to selectively breed a new type of corn that produces sweeter, saltier kernels. He starts with one plant that produces sweeter kernels and another plant that produces saltier kernels.

64 He performs several crosses and successfully produces a plant with sweeter, saltier kernels but discovers that his phenotype ratios are not consistent with his pea plant results. After examining his results, you suspect codominance. However, Mendel is not yet familiar with this concept. OBJECTIVE: Assuming that Mendel started with purebreds, design an experiment that illustrates this concept to Mendel. Include a hypothesis.

65 SAMPLE EXPERIMENT PROCEDURE: 1.Cross-fertilize parents with each other 2.Cross-fertilize F 1 with each parent to verify parents are purebreds 3.Self-fertilize F 1 offspring and compare ratios 4.Repeat

66 EXPECTED RESULTS: Using:A = sweet, a = not sweet B = salty, b = not salty If parent plants are purebreds, then: Positive results for codominance: F 1 :all sweet, salty (AB) F 2 :1 sweet, not salty (AA) 2 sweet, salty (AB) 1 not sweet, salty (BB)

67 Negative results for codominance: i.e. positive results for separate 2 traits F 1 :all sweet, salty (AaBb) F 2 :9 sweet, salty (1 AABB, 2 AABb, 2 AaBB, 4 AaBb) 3 sweet, not salty (1 AAbb, 2 Aabb) 3 not sweet, salty (1 aaBB, 2 aaBb) 1 not sweet, not salty (aabb)


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