1. Making linkage analysis simple

2. Making linkage analysis simple
(Do Ch. 5 problems!)

3. Bakers’ yeast
A single-celled eukaryote

4. Haploid and diploid
Fig. 5.14

5. Haploid and diploid
Clonal (mitotic) growth
Fig. 5.14

6. Haploid and diploid
Fig. 5.14

7. Haploid and diploid
Fig. 5.14

8. Why yeast?

9. Tetrad analysis
Fig 5.15

10. Tetrad analysis
Fig 5.15

11. Tetrad analysis
Cannot make histidine
Cannot make tryptophan
Fig 5.15

12. Tetrad analysis
Fig 5.15

13. Tetrad analysis
Fig 5.15

14. Tetrad analysis
Fig 5.15

15. Tetrad analysis
Fig 5.15

16. Tetrad analysis
Fig 5.15

17. Tetrad analysis
Fig 5.15
NPD = 4 recombinant progeny

18. Tetrad analysis
Fig 5.15

19. Tetrad analysis
Fig 5.15
T = 2 recomb, 2 non-recomb

20. Tetrad analysis example
Fig 5.15

21. Tetrad analysis example
“Number of recombinants = NPD•4 + T•2”
Fig 5.15

22. Tetrad analysis example
“Number of recombinants = NPD•4 + T•2”
“RF = NPD•4 + T•2 ”
4•Total # tetrads
Fig 5.15

23. Tetrad analysis example
“Number of recombinants = NPD•4 + T•2”
“RF = NPD•4 + T•2 ”
4•Total # tetrads
= NPD + 1/2T ”
Total # tetrads
Fig 5.15

24. Tetrad analysis example 2
Fig. 5.16

25. Tetrad analysis example 2
Fig. 5.16
If PD >> NPD, genes are linked.

26. Tetrad analysis If linked, second law does not hold;
Fig 5.15
If linked, second law does not hold;
<< 50% recombinants

27. Tetrad analysis
What if two crossovers?
Fig 5.15

28. Accurate genetic distances?
“Number of recombinants = NPD•4 + T•2”
“RF = NPD•4 + T•2 ”
4•Total # tetrads
= NPD + 1/2T ”
Total # tetrads
Where’s PD?

29. The real story: mapping functions
Fig. 5.17
Do Ch. 5, problem 35…

30. Bread mold

31. Bread mold
Fig. 5.14

32. Bread mold
Each pair is identical
Fig. 5.14

33. Mapping centromeric distance
Fig. 5.21

34. Mapping centromeric distance
Fig. 5.21

35. Mapping centromeric distance
Number of meioses with second-division patterns = number of crossovers between locus and centromere
Fig. 5.21