1. Exam #3 W 12/5 at 7-8:30pm in ETC 2. 108 for the 9am class and ECJ 1
Exam #3 W 12/5 at 7-8:30pm in ETC for the 9am class and ECJ for the noon class
Review T 12/4 at 5pm in WRW 102
Homework #4 due 12/3 (if needed)
Bonus #2 is posted

2. Grades:
A = 88.5+
B = 77.5
C = 65.5
Exam avg x homework + bonus = grade

3. Tracking two separate genes, for two separate traits, each with two alleles.
Ratio of 9:3:3:1
Fig 3.4

4. Box 2.2
Crossing-over
Meiosis:
In humans, crossing-over and independent assortment lead to over 1 trillion possible unique gametes.
(1,000,000,000,000)
Meiosis I
(Ind. Assort.)
Meiosis II
4 Haploid cells, each unique

5. Crossing over produces new allelic combinations
Fig 4.3

6. Homologous
pair of chromosomes

7. Longer regions have more crossovers and thus higher recombinant frequencies
Fig 4.10

8. Some crosses do not give the expected results

9. =25%
42%
41% 9% 8%

10. These two genes are on the same chromosome

12. By comparing recombination frequencies, a linkage map can be constructed
= 17 m.u.

13. Another test

14. 42 recombinants out of 381 offspring =
42/381
11% recombination

15. The probability of crossing over can be used to determine the spatial relationship of different genes
Fig 4.9

16. Double recombinants arise from two crossovers
Fig 4.11

17. Double recombinants can show gene order
Fig 4.12

18. What is the relationship between these 3 genes
What is the relationship between these 3 genes? What order and how far apart?
similar to pg 141

19. What is the relationship between these 3 genes
What is the relationship between these 3 genes? What order and how far apart?
similar to pg 141

20. Double crossover
similar to pg 141

21. Which order produces the double crossover?

22. Which order produces the double crossover?

23. We have the order. What is the distance?
similar to pg 141

24. Recombinants between st and ss: (50+52+5+3)/755 =14.6%
similar to pg 141

25. Recombinants between ss and e: (43+41+5+3)/755 =12.2%
similar to pg 141

26. Put it all together…
26.8 m.u. st ss e
14.6 m.u.
12.2 m.u.

27. Linkage map of Drosophila chromosome 2

28. Recombination is not completely random.
physical distance
linkage map
Yeast chromosome 3
Fig 4.13 and 20

29. It is rarely this simple.
Genotype
Phenotype
Genes code for proteins (or RNA). These gene products give rise to traits…
It is rarely this simple.
Figs

30. The relationship between genes and traits is often complex
Complexities include:
Complex relationships between alleles
Multiple genes controlling one trait
One gene controlling multiple traits
Environmental effects

31. The colors of peppers are determined by the interaction of several genes

32. Complexity of inheritance leads to genetic diversity.
Fig

33. Eye color: One trait controlled by multiple genes

34. Seven alleles and their interactions in leaf patterning of clover
Fig 6.7

35. The relationship between genes and traits is often complex
Complexities include:
Complex relationships between alleles
Multiple genes controlling one trait
One gene controlling multiple traits
Environmental effects

36. 1 gene
controlling
many traits

37. Mom = HS Dad = HS Dad H or S possible offspring 75% Normal
S=sickle-cell
H=normal
Sickle-Cell Anemia
Mom = HS
Dad = HS
Dad
H or S
possible offspring
75% Normal
25% Sickle-cell HH HS
H or S
Mom HS SS

38. Coincidence of malaria and sickle-cell anemia

39. Mom = HS Dad = HS possible offspring Oxygen transport: 75% Normal
S=sickle-cell
H=normal
Sickle-Cell Anemia
Mom = HS
Dad = HS
possible offspring
Oxygen transport:
75% Normal
25% Sickle-cell
Malaria resistance:
75% resistant
25% susceptible
Dad
H or S HH HS
H or S
Mom HS SS

40. The relationship between genes and traits is often complex
Complexities include:
Complex relationships between alleles
Multiple genes controlling one trait
One gene controlling multiple traits
Environmental effects

41. Next we will look at what DNA can tell us about the origins of Homo sapiens.

42. Exam #3 W 12/5 at 7-8:30pm in ETC 2. 108 for the 9am class and ECJ 1
Exam #3 W 12/5 at 7-8:30pm in ETC for the 9am class and ECJ for the noon class
Review T 12/4 at 5pm in WRW 102
Homework #4 due 12/3 (if needed)
Bonus #2 is posted