AIM:
How can we measure
  the evolution of
   populations?

Warm – up: List the 5
  factors in which
evolution can occur
Populations & Gene Pools
Populations & Gene Pools
• Concepts
  – a population is a localized group of
    interbreeding individuals
  – gene pool i...
Evolution of Populations
Evolution of Populations
• Evolution = change in allele frequencies
  in a population
  – hypothetical: what conditions wo...
Hardy-Weinberg Equilibrium




   G.H. Hardy           W. Weinberg
mathematician           physician
Hardy-Weinberg Equilibrium
   • Hypothetical, non-evolving population
      – preserves allele frequencies
   • Serves as ...
Hardy-Weinberg Theorem




     BB    Bb     bb
Hardy-Weinberg Theorem
• Counting Alleles




            BB       Bb   bb
Hardy-Weinberg Theorem
• Counting Alleles
  – assume 2 alleles = B, b




             BB          Bb   bb
Hardy-Weinberg Theorem
• Counting Alleles
  – assume 2 alleles = B, b
  – frequency of dominant allele (B) = p




       ...
Hardy-Weinberg Theorem
• Counting Alleles
  – assume 2 alleles = B, b
  – frequency of dominant allele (B) = p
  – frequen...
Hardy-Weinberg Theorem
• Counting Alleles
  – assume 2 alleles = B, b
  – frequency of dominant allele (B) = p
  – frequen...
Hardy-Weinberg Theorem
• Counting Alleles
  – assume 2 alleles = B, b
  – frequency of dominant allele (B) = p
  – frequen...
Hardy-Weinberg Theorem




     BB    Bb     bb
Hardy-Weinberg Theorem
• Counting Individuals




            BB           Bb   bb
Hardy-Weinberg Theorem
• Counting Individuals
  – frequency of homozygous dominant: p x p = p2




            BB         ...
Hardy-Weinberg Theorem
• Counting Individuals
  – frequency of homozygous dominant: p x p = p2
  – frequency of homozygous...
Hardy-Weinberg Theorem
• Counting Individuals
  – frequency of homozygous dominant: p x p = p2
  – frequency of homozygous...
Hardy-Weinberg Theorem
• Counting Individuals
  – frequency of homozygous dominant: p x p = p2
  – frequency of homozygous...
Hardy-Weinberg Theorem
• Counting Individuals
  – frequency of homozygous dominant: p x p = p2
  – frequency of homozygous...
H-W Formulas




BB    Bb       bb
H-W Formulas
• Alleles:        p+q=1




             BB      Bb     bb
H-W Formulas
• Alleles:        p+q=1
                   B




             BB        Bb   bb
H-W Formulas
• Alleles:        p+q=1
                     B   b



• Individuals:    p2 + 2pq + q2 = 1


             BB  ...
H-W Formulas
• Alleles:        p+q=1
                     B   b



• Individuals:    p2 + 2pq + q2 = 1
                   ...
H-W Formulas
• Alleles:        p+q=1
                     B   b



• Individuals:    p2 + 2pq + q2 = 1
                   ...
H-W Formulas
• Alleles:        p+q=1
                     B   b



• Individuals:    p2 + 2pq + q2 = 1
                   ...
Using Hardy-Weinberg Equation




        BB     Bb     bb
Using Hardy-Weinberg Equation
 population:
 100 cats
 84 black, 16 white
 How many of each
 genotype?



            BB   ...
Using Hardy-Weinberg Equation
 population:
 100 cats                   q2 (bb): 16/100 = .
 84 black, 16 white           1...
Using Hardy-Weinberg Equation
 population:
 100 cats                    q2 (bb): 16/100 = .
 84 black, 16 white           ...
Using Hardy-Weinberg Equation
 population:
 100 cats                    q2 (bb): 16/100 = .
 84 black, 16 white           ...
Using Hardy-Weinberg Equation
 population:
 100 cats                    q2 (bb): 16/100 = .
 84 black, 16 white           ...
Using Hardy-Weinberg Equation
 population:
 100 cats                    q2 (bb): 16/100 = .
 84 black, 16 white           ...
Using Hardy-Weinberg Equation
                  p2=.36    2pq=.48   q2=.16
Assuming               BB       Bb        bb
H-...
Using Hardy-Weinberg Equation
                  p2=.36    2pq=.48   q2=.16
Assuming               BB       Bb        bb
H-...
Using Hardy-Weinberg Equation
                  p2=.36    2pq=.48   q2=.16
Assuming               BB       Bb        bb
H-...
Using Hardy-Weinberg Equation
                  p2=.36    2pq=.48   q2=.16
Assuming               BB       Bb        bb
H-...
Using Hardy-Weinberg Equation
                    p2=.36    2pq=.48   q2=.16
Assuming                 BB       Bb        b...
Using Hardy-Weinberg Equation
                    p2=.36    2pq=.48   q2=.16
Assuming                 BB       Bb        b...
Application of H-W Principle
Application of H-W Principle
• Sickle cell anemia
Application of H-W Principle
• Sickle cell anemia
  – inherit a mutation in gene coding for
    hemoglobin
Application of H-W Principle
• Sickle cell anemia
  – inherit a mutation in gene coding for
    hemoglobin
     • oxygen-c...
Application of H-W Principle
• Sickle cell anemia
  – inherit a mutation in gene coding for
    hemoglobin
     • oxygen-c...
Application of H-W Principle
• Sickle cell anemia
  – inherit a mutation in gene coding for
    hemoglobin
     • oxygen-c...
Application of H-W Principle
• Sickle cell anemia
  – inherit a mutation in gene coding for
    hemoglobin
     • oxygen-c...
Application of H-W Principle
• Sickle cell anemia
  – inherit a mutation in gene coding for
    hemoglobin
     • oxygen-c...
Application of H-W Principle
• Sickle cell anemia
  – inherit a mutation in gene coding for
    hemoglobin
     • oxygen-c...
Application of H-W Principle
• Sickle cell anemia
  – inherit a mutation in gene coding for
    hemoglobin
     • oxygen-c...
Application of H-W Principle
• Sickle cell anemia
  – inherit a mutation in gene coding for
    hemoglobin
     • oxygen-c...
Sickle cell Frequency
Sickle cell Frequency
• High frequency of heterozygotes
  – 1 in 5 in Central Africans = HbHs
  – unusual for allele with ...
Sickle cell Frequency
• High frequency of heterozygotes
  – 1 in 5 in Central Africans = HbHs
  – unusual for allele with ...
Malaria


1




    2


        3
Malaria eukaryote parasite
             Single-celled
             (Plasmodium) spends part of its
             life cycle...
Malaria eukaryote parasite
             Single-celled
             (Plasmodium) spends part of its
             life cycle...
Malaria eukaryote parasite
             Single-celled
             (Plasmodium) spends part of its
             life cycle...
Malaria eukaryote parasite
             Single-celled
             (Plasmodium) spends part of its
             life cycle...
Heterozygote Advantage




           Frequency of sickle cell allele &
           distribution of malaria
Heterozygote Advantage
• In tropical Africa, where malaria is common:




                          Frequency of sickle ce...
Heterozygote Advantage
• In tropical Africa, where malaria is common:
  – homozygous dominant (normal) die of malaria: HbH...
Heterozygote Advantage
• In tropical Africa, where malaria is common:
  – homozygous dominant (normal) die of malaria: HbH...
Heterozygote Advantage
• In tropical Africa, where malaria is common:
  – homozygous dominant (normal) die of malaria: HbH...
Heterozygote Advantage
   • In tropical Africa, where malaria is common:
      – homozygous dominant (normal) die of malar...
Any Questions??
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1.7

  1. 1. AIM: How can we measure the evolution of populations? Warm – up: List the 5 factors in which evolution can occur
  2. 2. Populations & Gene Pools
  3. 3. Populations & Gene Pools • Concepts – a population is a localized group of interbreeding individuals – gene pool is collection of alleles in the population • remember difference between alleles & genes! – allele frequency is how common is that allele in the population • how many A vs. a in whole population
  4. 4. Evolution of Populations
  5. 5. Evolution of Populations • Evolution = change in allele frequencies in a population – hypothetical: what conditions would cause allele frequencies to not change? – non-evolving population REMOVE all agents of evolutionary change 1. very large population size (no genetic drift) 2. no migration (no gene flow in or out) 3. no mutation (no genetic change) 4. random mating (no sexual selection) 5. no natural selection (everyone is equally fit)
  6. 6. Hardy-Weinberg Equilibrium G.H. Hardy W. Weinberg mathematician physician
  7. 7. Hardy-Weinberg Equilibrium • Hypothetical, non-evolving population – preserves allele frequencies • Serves as a model (null hypothesis) – natural populations rarely in H-W equilibrium – useful model to measure if forces are acting on a population • measuring evolutionary change G.H. Hardy W. Weinberg mathematician physician
  8. 8. Hardy-Weinberg Theorem BB Bb bb
  9. 9. Hardy-Weinberg Theorem • Counting Alleles BB Bb bb
  10. 10. Hardy-Weinberg Theorem • Counting Alleles – assume 2 alleles = B, b BB Bb bb
  11. 11. Hardy-Weinberg Theorem • Counting Alleles – assume 2 alleles = B, b – frequency of dominant allele (B) = p BB Bb bb
  12. 12. Hardy-Weinberg Theorem • Counting Alleles – assume 2 alleles = B, b – frequency of dominant allele (B) = p – frequency of recessive allele (b) = q BB Bb bb
  13. 13. Hardy-Weinberg Theorem • Counting Alleles – assume 2 alleles = B, b – frequency of dominant allele (B) = p – frequency of recessive allele (b) = q • frequencies must add to 1 (100%), so: BB Bb bb
  14. 14. Hardy-Weinberg Theorem • Counting Alleles – assume 2 alleles = B, b – frequency of dominant allele (B) = p – frequency of recessive allele (b) = q • frequencies must add to 1 (100%), so: p+q=1 BB Bb bb
  15. 15. Hardy-Weinberg Theorem BB Bb bb
  16. 16. Hardy-Weinberg Theorem • Counting Individuals BB Bb bb
  17. 17. Hardy-Weinberg Theorem • Counting Individuals – frequency of homozygous dominant: p x p = p2 BB Bb bb
  18. 18. Hardy-Weinberg Theorem • Counting Individuals – frequency of homozygous dominant: p x p = p2 – frequency of homozygous recessive: q x q = q2 BB Bb bb
  19. 19. Hardy-Weinberg Theorem • Counting Individuals – frequency of homozygous dominant: p x p = p2 – frequency of homozygous recessive: q x q = q2 – frequency of heterozygotes: (p x q) + (q x p) = 2pq BB Bb bb
  20. 20. Hardy-Weinberg Theorem • Counting Individuals – frequency of homozygous dominant: p x p = p2 – frequency of homozygous recessive: q x q = q2 – frequency of heterozygotes: (p x q) + (q x p) = 2pq • frequencies of all individuals must add to 1 (100%), so: BB Bb bb
  21. 21. Hardy-Weinberg Theorem • Counting Individuals – frequency of homozygous dominant: p x p = p2 – frequency of homozygous recessive: q x q = q2 – frequency of heterozygotes: (p x q) + (q x p) = 2pq • frequencies of all individuals must add to 1 (100%), so: p2 + 2pq + q2 = 1 BB Bb bb
  22. 22. H-W Formulas BB Bb bb
  23. 23. H-W Formulas • Alleles: p+q=1 BB Bb bb
  24. 24. H-W Formulas • Alleles: p+q=1 B BB Bb bb
  25. 25. H-W Formulas • Alleles: p+q=1 B b • Individuals: p2 + 2pq + q2 = 1 BB Bb bb
  26. 26. H-W Formulas • Alleles: p+q=1 B b • Individuals: p2 + 2pq + q2 = 1 BB BB Bb bb
  27. 27. H-W Formulas • Alleles: p+q=1 B b • Individuals: p2 + 2pq + q2 = 1 BB bb BB Bb bb
  28. 28. H-W Formulas • Alleles: p+q=1 B b • Individuals: p2 + 2pq + q2 = 1 BB Bb bb BB Bb bb
  29. 29. Using Hardy-Weinberg Equation BB Bb bb
  30. 30. Using Hardy-Weinberg Equation population: 100 cats 84 black, 16 white How many of each genotype? BB Bb bb
  31. 31. Using Hardy-Weinberg Equation population: 100 cats q2 (bb): 16/100 = . 84 black, 16 white 16 How many of each q (b): √.16 = 0.4 genotype? p (B): 1 - 0.4 = 0.6 BB Bb bb What are the genotype frequencies?
  32. 32. Using Hardy-Weinberg Equation population: 100 cats q2 (bb): 16/100 = . 84 black, 16 white 16 How many of each q (b): √.16 = 0.4 genotype? p (B): 1 - 0.4 = 0.6 BB Bb bb Must are the population is in H-W equilibrium! What assume genotype frequencies?
  33. 33. Using Hardy-Weinberg Equation population: 100 cats q2 (bb): 16/100 = . 84 black, 16 white 16 How many of each q (b): √.16 = 0.4 genotype? p (B): 1 - 0.4 = 0.6 p2=.36 BB Bb bb Must are the population is in H-W equilibrium! What assume genotype frequencies?
  34. 34. Using Hardy-Weinberg Equation population: 100 cats q2 (bb): 16/100 = . 84 black, 16 white 16 How many of each q (b): √.16 = 0.4 genotype? p (B): 1 - 0.4 = 0.6 p2=.36 2pq=.48 BB Bb bb Must are the population is in H-W equilibrium! What assume genotype frequencies?
  35. 35. Using Hardy-Weinberg Equation population: 100 cats q2 (bb): 16/100 = . 84 black, 16 white 16 How many of each q (b): √.16 = 0.4 genotype? p (B): 1 - 0.4 = 0.6 p2=.36 2pq=.48 q2=.16 BB Bb bb Must are the population is in H-W equilibrium! What assume genotype frequencies?
  36. 36. Using Hardy-Weinberg Equation p2=.36 2pq=.48 q2=.16 Assuming BB Bb bb H-W equilibrium
  37. 37. Using Hardy-Weinberg Equation p2=.36 2pq=.48 q2=.16 Assuming BB Bb bb H-W equilibrium Null hypothesis
  38. 38. Using Hardy-Weinberg Equation p2=.36 2pq=.48 q2=.16 Assuming BB Bb bb H-W equilibrium Null hypothesis BB Bb bb
  39. 39. Using Hardy-Weinberg Equation p2=.36 2pq=.48 q2=.16 Assuming BB Bb bb H-W equilibrium Null hypothesis BB Bb bb Sampled data
  40. 40. Using Hardy-Weinberg Equation p2=.36 2pq=.48 q2=.16 Assuming BB Bb bb H-W equilibrium Null hypothesis p2=.74 2pq=.10 q2=.16 BB Bb bb Sampled data How do you explain the data?
  41. 41. Using Hardy-Weinberg Equation p2=.36 2pq=.48 q2=.16 Assuming BB Bb bb H-W equilibrium Null hypothesis p2=.20 =.74 2pq=.64 2pq=.10 q2=.16 BB Bb bb Sampled data How do you explain the data?
  42. 42. Application of H-W Principle
  43. 43. Application of H-W Principle • Sickle cell anemia
  44. 44. Application of H-W Principle • Sickle cell anemia – inherit a mutation in gene coding for hemoglobin
  45. 45. Application of H-W Principle • Sickle cell anemia – inherit a mutation in gene coding for hemoglobin • oxygen-carrying blood protein
  46. 46. Application of H-W Principle • Sickle cell anemia – inherit a mutation in gene coding for hemoglobin • oxygen-carrying blood protein • recessive allele = HsHs
  47. 47. Application of H-W Principle • Sickle cell anemia – inherit a mutation in gene coding for hemoglobin • oxygen-carrying blood protein • recessive allele = HsHs – normal allele = Hb
  48. 48. Application of H-W Principle • Sickle cell anemia – inherit a mutation in gene coding for hemoglobin • oxygen-carrying blood protein • recessive allele = HsHs – normal allele = Hb – low oxygen levels causes RBC to sickle
  49. 49. Application of H-W Principle • Sickle cell anemia – inherit a mutation in gene coding for hemoglobin • oxygen-carrying blood protein • recessive allele = HsHs – normal allele = Hb – low oxygen levels causes RBC to sickle • breakdown of RBC
  50. 50. Application of H-W Principle • Sickle cell anemia – inherit a mutation in gene coding for hemoglobin • oxygen-carrying blood protein • recessive allele = HsHs – normal allele = Hb – low oxygen levels causes RBC to sickle • breakdown of RBC • clogging small blood vessels
  51. 51. Application of H-W Principle • Sickle cell anemia – inherit a mutation in gene coding for hemoglobin • oxygen-carrying blood protein • recessive allele = HsHs – normal allele = Hb – low oxygen levels causes RBC to sickle • breakdown of RBC • clogging small blood vessels • damage to organs
  52. 52. Application of H-W Principle • Sickle cell anemia – inherit a mutation in gene coding for hemoglobin • oxygen-carrying blood protein • recessive allele = HsHs – normal allele = Hb – low oxygen levels causes RBC to sickle • breakdown of RBC • clogging small blood vessels • damage to organs – often lethal
  53. 53. Sickle cell Frequency
  54. 54. Sickle cell Frequency • High frequency of heterozygotes – 1 in 5 in Central Africans = HbHs – unusual for allele with severe detrimental effects in homozygotes • 1 in 100 = HsHs • usually die before reproductive age Why is the Hs allele maintained at such high levels in African populations?
  55. 55. Sickle cell Frequency • High frequency of heterozygotes – 1 in 5 in Central Africans = HbHs – unusual for allele with severe detrimental effects in homozygotes • 1 in 100 = HsHs • usually die before reproductive age Why is the Hs allele maintained at such high levels in African populations? Suggests some selective advantage of being heterozygous…
  56. 56. Malaria 1 2 3
  57. 57. Malaria eukaryote parasite Single-celled (Plasmodium) spends part of its life cycle in red blood cells 1 2 3
  58. 58. Malaria eukaryote parasite Single-celled (Plasmodium) spends part of its life cycle in red blood cells 1 2 3
  59. 59. Malaria eukaryote parasite Single-celled (Plasmodium) spends part of its life cycle in red blood cells 1 2 3
  60. 60. Malaria eukaryote parasite Single-celled (Plasmodium) spends part of its life cycle in red blood cells 1 2 3
  61. 61. Heterozygote Advantage Frequency of sickle cell allele & distribution of malaria
  62. 62. Heterozygote Advantage • In tropical Africa, where malaria is common: Frequency of sickle cell allele & distribution of malaria
  63. 63. Heterozygote Advantage • In tropical Africa, where malaria is common: – homozygous dominant (normal) die of malaria: HbHb Frequency of sickle cell allele & distribution of malaria
  64. 64. Heterozygote Advantage • In tropical Africa, where malaria is common: – homozygous dominant (normal) die of malaria: HbHb – homozygous recessive die of sickle cell anemia: HsHs Frequency of sickle cell allele & distribution of malaria
  65. 65. Heterozygote Advantage • In tropical Africa, where malaria is common: – homozygous dominant (normal) die of malaria: HbHb – homozygous recessive die of sickle cell anemia: HsHs – heterozygote carriers are relatively free of both: HbHs Frequency of sickle cell allele & distribution of malaria
  66. 66. Heterozygote Advantage • In tropical Africa, where malaria is common: – homozygous dominant (normal) die of malaria: HbHb – homozygous recessive die of sickle cell anemia: HsHs – heterozygote carriers are relatively free of both: HbHs • survive more, more common in population Hypothesis: In malaria-infected cells, the O2 level is lowered enough to cause sickling which kills the cell & destroys the parasite. Frequency of sickle cell allele & distribution of malaria
  67. 67. Any Questions??

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