1. Practical 3 Meiosis Gametogenesis

3. Sexual reproduction Life cycle: haploid phase (gametes) diploid phase (somatic cells) 2n 2n meiosis meiosis n n Gametes (haploid) sperm oocyte fertilization 2n n + n = 2n zygote ♂ ♀

6. Meiotic division 2n 1 st meiotic division 2 nd meiotic division n n n n n n

16. Task A – result male female Normal combination of gonosomes X;Y translocation XX XY „ XX-male“ „ XY-female“

17. Hermaphroditism – possible consequence of sex chromosome abnormalities

18. Prophase of the 1 st meiotic division next periods

19. Pachytene

22. Terminal phases of meiotic division prophase metaphase + anaphase 2 nd meiotic division (homeotypic) 1 st meiotic division (heterotypic) Separation of double-chromatid homologous chromosomes

23. Metaphase I Metaphase I

24. Anaphase I X Anaphase II

27. Spermatogenesis n n 1st meiotic division 2nd meiotic division n n primary spermatocyte secondary spermatocyte sperm n n 2n

28. Oogenesis n n 1st meiotic division 2nd meiotic division n n primary oocyte secondary oocyte mature oocyte n n 2n polar bodies polar body

29. A schedule of oocyte development Prophase I fetus childhood – dictyotene mature ovary fertilization

30. Spermatogenesis X Oogenesis

33. Practical tasks

37. Task 3 : Changes of nuclear DNA concentration during the cell cycle G 1 G 2 S M G 1 C 2C G 1 G 2 S M 1 M 2 G 1 Cell cycle + mitosis Cell cycle + meiosis Nuclear DNA content

38. Results

39. Task 3: Observation of meiosis in the grasshopper testis

40. Task 4: Disjunction of the sex chromosomes during meiosis Scheme A Scheme B XY X Y X X Y Y

41. Task 5: Changes of nuclear DNA concentration during the cell cycle G 1 G 2 S M G 1 C 2C G 1 G 2 S M 1 M 2 G 1 Cell cycle + mitosis Cell cycle + meiosis Nuclear DNA

46. ICSI (intracytoplasmatic sperm injection)

47. ICSI protocol

49. Presentation Ethical issues of assisted reproduction

51. See you next week!