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Chapter 9

Chapter 9. Who’s the Father of Modern Genetics ?. Gregor Mendel!. 1843: Austrian monastery Job = gardening 1851: University of Vienna Studied math and science Statistics!!!. What did Mendel Experiment with?. What plant? What about these plants?

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Chapter 9

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  1. Chapter 9

  2. Who’s the Father of Modern Genetics? Gregor Mendel! • 1843: • Austrian monastery • Job = • gardening • 1851: • University of Vienna • Studied math and science • Statistics!!!

  3. What did Mendel Experiment with? • What plant? • What about these plants? • Characteristics- heritable feature • Traits- genetically determined variant of a characteristic

  4. Characteristics and Traits Dominant Recessive

  5. Mendel’s Observations • Seeds from purple flowers produce... • Seeds from white flowers produce... • Seeds from tall plants... • Seeds from short pants... • This always true? NO!!!

  6. 3 Steps of Mendel’s Experiments 1. P:

  7. Self Pollination

  8. 2. F1:

  9. Cross Pollination

  10. 3. F2: Ratio of offspring:

  11. P generation Cross-pollination F1 Generation Self-pollination F2 Generation Statistics 3 of 4 are purple

  12. Mendel’s Experiments Continue... • 100s of times • Lots of other traits • All the same results!! • 3:1 phenotypic ratio

  13. Mendel’s Conclusions • What did he conclude? • Something in the plant was a controlling factor • What Did Mendel Hypothesize About Passing Traits? • Each trait independently controlled

  14. Review of His Results

  15. Recessive vs. Dominant • Expressed if present at all AA, Aa • “Masked” when dominant present AA, Aa • Expressed if no dominant present aa

  16. What are YOU? Class Ratios:

  17. Conclusions: LAWS • Law of segregation • Pair of factors are separated during production of gametes. • Why/How? • Online Animation!

  18. Conclusions: LAWS • Crossed plants w/2 different characteristics (flower color, seed color) • Offspring showed traits from dominant factors of each • Law of Independent assortment • characteristics are inherited independent of each other • Another Great Animation!

  19. Pp Yy PY Py pY py Purple flower Yellow seed Purple flower Green seed White flower Yellow seed White flower Green seed

  20. Pair Share! • 1st person: explain the Law of Segregation • 2nd person: explain the Law of Independent Assortment

  21. 9.2 Part AGENETIC CROSSES

  22. Support for Mendel’s Conclusions Molecular Genetics Study of structure and function of genes and chromosomes “Factors” are now called ALLELES!

  23. Gene vs. Allele Piece of DNA Transcribed  proteins Several on each chromosome • Variants of genes • Represented by letters Symbols: • Dom (capital)/Rec (small) • Flower color: P and p • Dom means... • Rec means...

  24. Genome?

  25. GENOTYPE AND PHENOTYPE? Purple White Genotype? Ex: Phenotype? Ex:

  26. YES!!!! Can different genotypes show the same phenotype?

  27. Homozygous and Heterozygous Refer to genotypic or phenotypic? Homozygous Both alleles are SAME AA or aa Heterozygous Alleles are DIFFERENT Aa

  28. What’s PROBABILITY? # of times expected Probability = # of times could happen Likelihood of something happening Percent, decimal or fraction

  29. PROBABILITY PRACTICE = • 1000 plants • 700 terminal flowers • 300 axial flowers • What is the probability that the next plant will have terminal flowers? • Axial?

  30. What’s a MONOHYBRID CROSS? eggs sperm • Only one characteristic is tracked • Produces a mono-hybrid • AA x aa  Aa • What’s a Punnett Square? • Diagram used to predict probabilities of inherited traits in offspring

  31. 6 types of monohybrid crosses: Homozygous x Homozygous Homozygous x Heterozygous Heterozygous x Heterozygous Testcross Incomplete Dominance Codominance

  32. Homozygous dom x Hom rec Probability

  33. Homozygous Dom x Homozygous Rec What genotypes? Probability of Purple Flowers? Probability of Heterozygous? Remember Mendel’s Experiment?

  34. Heterozygous x Heterozygous Probability

  35. Heterozygous x Heterozygous Black coated bunnies (brown is recessive) What genotypes? Probability for Black? Homozygous? Heterozygous?

  36. Homozygous Dominant x Heterozygous Probability

  37. Hom. Dom. x Heterozygous Black guinea pigs (dom), brown (rec) What genotypes? Probability for Black? Homozygous? Heterozygous?

  38. Testcross: animation What genotype do you test it with? Hom recessive x Unknown genotype You are Given a Black Guinea pig. How do you determine the Genotype? If you end up with three black guinea pigs and one brown what was the genotype of the unknown guinea pig?

  39. REVIEW • Homozygous? • Heterozygous? • Genotype? • Phenotype? • Testcross? • Dominant? • Recessive? • Practice w/monohybrid punnett squares • Square activity

  40. OPENER, Wed. 12/2 You’re TURNING THIS IN, in 7 minutes!! Use “D” and “d” for the alleles, make a punnett square for each: D = Dodo Head d = Wiz Kid 1. Purebred Dodo Head x Wiz kid 2. Heterozygous x Wiz kid 3. Hybrid Dodo Head x Homozygous Dodo Head Then, for each scenario, find the probability of: a. Dodo Heads? b. Wiz Kids? c. Purebred Dodo Heads d. Heterozygous offspring

  41. OPENER, Wed. 12/2 You’re TURNING THIS IN, in 7 minutes!! Use “D” and “d” for the alleles, make a punnett square for each: D = Dodo Head d = Wiz Kid 1. Purebred Dodo Head x Wiz kid 2. Heterozygous x Wiz kid 3. Hybrid Dodo Head x Homozygous Dodo Head Then, for each scenario, find the probability of: a. Dodo Heads? b. Wiz Kids? c. Purebred Dodo Heads d. Heterozygous offspring

  42. OPENER, Wed. 12/2 You’re TURNING THIS IN, in 7 minutes!! Use “D” and “d” for the alleles, make a punnett square for each: D = Dodo Head d = Wiz Kid 1. Purebred Dodo Head x Wiz kid 2. Heterozygous x Wiz kid 3. Hybrid Dodo Head x Homozygous Dodo Head Then, for each scenario, find the probability of: a. Dodo Heads? b. Wiz Kids? c. Purebred Dodo Heads d. Heterozygous offspring

  43. OPENER, Wed. 12/2 You’re TURNING THIS IN, in 7 minutes!! Use “D” and “d” for the alleles, make a punnett square for each: D = Dodo Head d = Wiz Kid 1. Purebred Dodo Head x Wiz kid 2. Heterozygous x Wiz kid 3. Hybrid Dodo Head x Homozygous Dodo Head Then, for each scenario, find the probability of: a. Dodo Heads? b. Wiz Kids? c. Purebred Dodo Heads d. Heterozygous offspring

  44. Monohybrid Cross Lab • Alleles, gametes, genotypes, phenotypes, Punnett Squares, & probabilities • Write your BAG #s on your data sheet! • COUNT all of your pieces before you begin • You’re drawing from the bags FORTY times today...get going! Follow the directions CAREFULLY! • We’ll finish up after the lab with more examples.

  45. 40 trials

  46. Homework: Earth Force Assignment Family History—Health Surveys And...book:

  47. 9.2 B MORE Genetic Crosses

  48. Some Weirdo Stuff! Incomplete dominance Codominance Multiple alleles Polygenic traits

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