1. EVIDENCE FROM GENETICS EVIDENCE FROM GENETICS

2. Can you answer this? Can you answer this?  Which represents a monohybrid cross between a homozygous recessive and a heterozygote?  A) Tt x Tt  B) ttmm x TtMm  C) tt x Tt  D) ttmm x TTMM

3. Can you answer this? Can you answer this? In rats, black fur is dominant over white. If a white rat is crossed with a heterozygous black rat, what is the likely % of the offspring that will be white? A) 0% B) 25% C) 50% D) 75%

4. And can you answer this? And can you answer this? Which of the following pairs of crosses results in the same phenotypic ratios? A)Aa x Aa and AA x aa B)AA x aa and AA x Aa C)AA x Aa and Aa x aa D)None of the above

5. EVIDENCE FROM GENETICS EVIDENCE FROM GENETICS  Deduction: If the hypothesis of evolution is correct, then we should see evidence of this in genetics  Background: Gregor Mendel (1822-1884 Experiments with the garden pea. His paper in 1866 established the field of genetics.

6. MENDEL’S GARDEN MENDEL’S GARDEN

7. Mendel at work Mendel at work

9. Mendel’s Traits

10. Monohybrid Crosses (=Breeding experiments involving one trait) Monohybrid Crosses (=Breeding experiments involving one trait)  Pea plants  P Tall x Tall Short x Short  F 1 All Tall All Short

11. Monohybrid Crosses (=Breeding experiments involving one trait) Monohybrid Crosses (=Breeding experiments involving one trait)  Pea plants  P Tall x Tall Short x Short  F 1 All Tall All Short  F 2 All Tall The tall trait is dominant

12. Monohybrid Crosses (=Breeding experiments involving one trait) Monohybrid Crosses (=Breeding experiments involving one trait)  Pea plants  P Tall x Tall Short x Short  F 1 All Tall All Short  F 2 F 2 x F 2 All Tall

13. Monohybrid Crosses (=Breeding experiments involving one trait) Monohybrid Crosses (=Breeding experiments involving one trait)  Pea plants  P Tall x Tall Short x Short  F 1 All Tall All Short  F 2 F 2 x F 2  F 3 75% Tall, 25% Short All Tall

14. MENDEL’S TRAITS  5474/1850=2.96  6022/2001=3.01  882/299=2.95  428/152=2.82  705/224=3.15  651/207=3.14  787/277=2.84

15. MENDEL’S TRAITS  5474/1850=2.96  6022/2001=3.01  882/299=2.95  428/152=2.82  705/224=3.15  651/207=3.14  787/277=2.84

16. Mendel analyzes the data Traits passed in the gametes Pollen (sperm) & eggs Note: ¾ Tall= TT, Tt, tT ¼ Short= tt ¼ Short= tt 3:1 Phenotypic Ratio

17. Terms and Principles Terms and Principles  Dominant (e.g. Tall)  Recessive (e.g. Short)  Phenotype (visible characteristics)  Genotype (genetic characteristics)  Particulate theory of inheritance= 2 particles (factors) determine a trait 2 particles (factors) determine a trait

18. Using a Punnett Square T t T t T TT Tt T TT Tt t Tt tt t Tt tt Alleles= Alternative forms of the same gene (T or t) Suppose Tt X Tt

19. Using a Punnett Square Eggs Eggs T t T t T TT Tt T TT TtPollen t Tt tt t Tt tt Tall Short

20. Using a Punnett Square T t T t T TT Tt T TT Tt t Tt tt t Tt tt Homozygous condition= both alleles are alike (TT or tt)

21. Using a Punnett Square T t T t T TT Tt T TT Tt t Tt tt t Tt tt Heterozygous condition= both alleles are different (Tt)

22. Clicker Question  Blue eyes (b) are recessive to brown (B). Suppose 2 parents had 11 children: 6 with blue and 5 with brown. Which of these statements is most likely to be right? A)Both parents had blue eyes. B)One parent had blue & the other was homozygous dominant C)Both parents had brown eyes. D)One parent had blue & the other was heterozygous E)Both parents were heterozygous.

23. Dihybrid Crosses (=Breeding experiments involving two traits) Round (R) or Wrinkled (r) seeds Round (R) or Wrinkled (r) seeds Yellow (Y) or Green (y) seeds Yellow (Y) or Green (y) seeds P RRYY x rryy F 1 RrYy Genotype Round Yellow Phenotype Round Yellow Phenotype

24. Dihybrid Cross RrYy x RrYy Dihybrid Cross RrYy x RrYy

28. Clicker Question What belongs in the red square? Clicker Question What belongs in the red square?  A) RRYY  B) RrYY  C rrYy  D) rrYY  E) rryy

29. Dihybrid Cross RrYy x RrYy Dihybrid Cross RrYy x RrYy

30. Clicker Question: How many wrinkled green seeds will there be out of 16 possibilities?  A) All 16  B) 9 out of 16  C) 50%  D) 3 0ut of 16  E) 1 out of 16

31. Clicker Question: How many wrinkled green seeds will there be out of 16 possibilities?  A) All 16  B) 9 out of 16  C) 50%  D) 3 0ut of 16  E) 1 out of 16

32. Dihybrid Cross RrYy x RrYy Dihybrid Cross RrYy x RrYy 9: 3: 3: 1 9: 3: 3: 1 Round Round Wrinkled Wrinkled Yellow Green Yellow Green

33. Principle of Independent Assortment Principle of Independent Assortment = Factors (genes) sort independently of one another. i.e. all possible combinations of Y and y and R and r occur BUT BUT

34. What if RY are linked together & ry are linked together ? Non Independent Assortment

35. Can you answer this? Can you answer this?  Which represents a monohybrid cross between a homozygous recessive and a heterozygote?  A) Tt x Tt  B) ttmm x TtMm  C) tt x Tt  D) ttmm x TTMM

36. Can you answer this? Can you answer this? In rats, black fur is dominant over white. If a white rat is crossed with a heterozygous black rat, what is the likely % of the offspring that will be white? A) 0% B) 25% C) 50% D) 75%

37. And can you answer this? And can you answer this? Which of the following pairs of crosses results in the same phenotypic ratios? A)Aa x Aa and AA x aa B)AA x aa and AA x Aa C)AA x Aa and Aa x aa D)None of the above

38. According to J.K. Rowling wizards & witches can be born from pure bloods or muggles. Suppose the wizard/witch trait is recessive (m) and the muggle trait is dominant (M)  Hermione is a witch born of muggle parents. If her parents had another child what are the chances that that one also would be a wizard or witch? A)0% B)25% C)50% D)75% E)100%