שיטות מיפוי נוספות

1. שיטותמיפוינוספות • תדירותרקומבינציהמהכלאהעצמית • שימושבכרומוזוםYכ-'בוחן' • "הגבול" ביןתאחיזהלהפרדהעצמית –2C • התחשבותבשיחלופיםשלארואים – "mapping function” • טטרדות – מיוזותבודדות, ומיפויביןגןלצנטרומר

4. The yeast Saccharomyces cerevisiae is commonly used as a model system =Budding Yeast =Bakers Yeast

5. The yeast Saccharomyces cerevisiae is clearly the most ideal eukaryotic microorganism for biological studies. The "awesome power of yeast genetics" has become legendary and is the envy of those who work with higher eukaryotes. The complete sequence of its genome has proved to be extremely useful as a reference towards the sequences of human and other higher eukaryotic genes. Furthermore, the ease of genetic manipulation of yeast allows its use for conveniently analyzing and functionally dissecting gene products from other eukaryotes. --Fred Sherman

6. Major advantages of the budding yeast as a genetic system • Grows fast • Cheap • Compact genome, fully sequenced since 1996. • Easy to handle • Superb Genetics, Biochemistry, Molecular Biology • Easy to transform, high efficiency of gene targeting

7. Major characteristic of the budding yeast • Unicellular Eukaryote • Grows by budding • 16 linear chromosomes • Generation Time: ~100 min • Can exist as stable diploid or haploid

8. Yeast: A model eukaryote "for their discoveries of key regulators of the cell cycle" The Nobel Prize in Physiology or Medicine 2001 Yeasts – the ultimate model eukaryote for unicellular issues and some basic cell-cell interactions Yeast studies have broken new ground in: Cytoskeleton functions transcription mechanisms** cell cycle** transcriptional regulation organelle biogenesis chromatin modification secretion* signal transduction protein targeting mechanisms protein degradation* chromosome replication DNA repair genome dynamics retroviral packaging prions recombination mechanisms ageing function of new genes metabolism protein modification *Lasker Award **Nobel Prize Paul Nurse Tim Hunt Lee Hartwaell Randy W. Schekman James E. Rothman Thomas C. Südhof The Nobel Prize in Physiology or Medicine 2013 for their discoveries of machinery regulating vesicle traffic, a major transport system in our cells

9. What is yeast? • Yeast - a fungus that divides to yield individual separated cells (as opposed to molds- mycelium) • Saccharomyces cerevisiae (budding yeast) • baker’s yeast closely related to brewer’s yeasts grows on rotting fruits • Schizosaccharomyces pombe (fission yeast) • African brewer’s yeast • Saccharomyces relatives • (S. bayanus, S. paradoxus, etc.) • Candida albicans • Cryptococcus neoformans

10. Yeast life cycle

11. Yeast cell cycle (mitosis) • morphology reflects cell cycle position • same in haploids and diploids • major control point is ‘start’-- • cells can choose mitosis, meiosis or mating • depends on ploidy, env. & presence of partner Major control point is at G1/S Morphology + nuclear localization and MT localization indicates the precise stage of the cell cycle

14. Mendel’s rules are relevant for organisms that sexually reproduce: diploid/haploid • Plants, Animals, many Mora… Those that ‘do’ meiosis

16. Haploid Mitosis

17. Diploid Mitosis

18. Haploid Mitosis Diploid Mitosis

19. 1n 1n 1n 2 1 Of diploid Of haploid

20. Centromere mapping

21. Centromere mapping Nonsister chromatids do not cross over First-division segregation pattern or MI pattern

24. n = 2 -> 4 2 1 1 1 S

25. Centromere mapping Nonsister chromatids do not cross over First-division segregation pattern or MI pattern

26. Centromere mapping Nonsister chromatids cross over Second-division segregation pattern or MII pattern

37. 1. The loci are on separate chromosomes 2. The loci are on opposite sides of the centromere on the same chromosome 3. The loci are on the same side of the centromere on the same chromosome

38. Unordered tetrads B a B a Mating b A b A Heterozygous diploid B a Meiosis B a b A b Tetrad A BA Ba BA BA Ba Ba Tetrad Dissection ba bA ba ba bA bA NPD PDT TT

39. Yeast tetrad analysis (classic method) tetrad Step3: let the spores grow into colonies Step1: separate spores by micromanipulation with a glass needle Step2: place the four spores from each tetrad in a row on an agar plate

40. Classical approach (tetrad dissection) Tetrad Dissection NPD PDT TT Tetrad bni1∆ bnr1∆ BA Ba BA BA Ba Ba ba bA ba ba bA bA

42. Perkin formula Map distance=50(T+6NPD) m.u

43. What PD, NPD and T values are expected when dealing with unlinked genes? B b Mating B b a a a A a a a A a B Meiosis a a B a b a A b A Tetrad Heterozygous diploid BA Ba BA BA Ba Ba Tetrad Dissection ba bA ba ba bA bA NPD PDT TT

44. What PD, NPD and T values are expected when dealing with unlinked genes? The sizes of the PD and NPD classes will be equal as a result of independent assortment. The T class can be produced only form a crossover between the specific loci and the and their respective centromeres B b Mating B b a a a A a a a A a B a Meiosis a B a a b A b A Tetrad Heterozygous diploid BA Ba BA BA Ba Ba Tetrad Dissection ba bA ba ba bA bA NPD PDT TT

45. שיטותמיפוינוספות • תדירותרקומבינציהמהכלאהעצמית • שימושבכרומוזוםYכ-'בוחן' • "הגבול" ביןתאחיזהלהפרדהעצמית –2C • התחשבותבשיחלופיםשלארואים – "mapping function” • טטרדות – מיוזותבודדות, ומיפויביןגןלצנטרומר

46. Haldane’s mapping function

47. התחשבות בשיחלופים שלא רואים – "mapping function”

48. התחשבות בשיחלופים שלא רואים – "mapping function” A formula that relates RF values to “real” physical distance m-is the mean number of cross overs that occur in a segment per meiosis

49. התחשבות בשיחלופים שלא רואים – "mapping function”

50. MESSAGE The inherent tendency of multiple crossovers to lead to an underestimate of map distance can be circumvented by the use of map function (in any organism) and by the Perkin formula (in tetrad-producing organisms such as fungi)