Genetic Inheritance and Linkage Map Analysis Exam Review

1. Exam #3 W 12/5 at 7-8:30pmin ETC 2.108 for the 9am class and ECJ 1.202 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 0.88 + 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 Recombinant Fig 4.11

17. Double recombinants can show gene order Fig4.12

18. 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 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 linkagemap Yeast chromosome 3 Fig 4.13 and 20

29. Genotype Phenotype Genes code for proteins (or RNA). These gene products give rise to traits… It is rarely this simple. Figs 1.15-17

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 3.14+.16

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

38. Coincidence of malaria and sickle-cell anemia

39. 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 HS HH 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 7-8:30pmin ETC 2.108 for the 9am class and ECJ 1.202 for the noon class • Review T 12/4 at 5pm in WRW 102 • Homework #4 due 12/3 (if needed) • Bonus #2 is posted