1. CO 04 The chromosome theory of inheritance

2. Fig. 4.5 Metaphase chromosome can be classified by centromere position

3. Fig. 4.6 Karyotype of a human male Metaphase chromosomes

4. Table 4.1 Human: Y makes the difference. Drosophila: ratio of number of X chromosome to copy number of autosome Mentally retarded Y is necessary for male fertility

5. Fig. 4.7 Mitosis Ensures that Every Cell in an Organism Carries the Same chromosomes

6. Fig. 4.8

7. Fig. 4.9

8. Fig. 4.10 Syncytium: a cell with two or more nuclei Red: chromosome Green: spindle fibers

9. Fig. 4.11 Checkpoints help regulate the cell cycle

10. Fig. 4.12 Meiosis Reduction division Equational division

11. Fig. 4.13a Prophase I in meiosis Chromosome condensation Pairing of homologous chromosomes Reciprocal exchange of the genetic information tetrad

12. Fig. 4.13d

13. Fig. 4.13b Meiosis I: metaphase Chiasma ensures proper segregation of homologous chromosomes

14. Fig. 4.13e Meiosis I interphase

15. Fig. 4.13c Meiosis II

16. Fig. 4.13f Meiosis II

17. Segregation during meiosis Segregation error: trisomies trisomy 21: Down syndrome extra X : Klinefeller male Nondisjunction

18. Fig. 4.16 Male donkey: 31 autosomes Female horse:32 autosomes Hybrid animal: mule

19. Fig. 4.17 Meiosis contributes to genetic diversity 2 13 =10 7

20. Gametogenesis (gamete formation) Germ cells (embryonic germ cells) mitosis Primary cells (diploid) meiosis gametes differentiation

21. Primary oocytes Oogenesis: asymmetric meiotic division 500,000 diplotene Diploid germ cells (oogonia) at metaphase II

22. Male germ cells Meiosis I Meiosis II 20 days mitosis Spermatogenesis: symmetric meiotic division

23. Validation of chromosome theory of inheritance 1.The chromosome theory correlates Mendel’s law with chromosome behavior during meiosis. 2. The transmission of particular chromosomes coincides with the transmission of specific traits

24. Fig. 4.20 X-linkage explains the inheritance of alleles of the white gene Criss-cross inheritance: The male inherit their eye color from their mothers, and vice vesa.

25. Fig. 4.21 Nondisjunction 1/2000 1/2000, W+ male; w female Cytologically with two X chromosomes

26. Fig. 4.22 Sex chromosome-linked disease Red-green color blindness (recessive) 8% man, 0.44% women Maternal grandfatehr 50% grandson

27. Fig. 4.23 Five properties of X-linked recessive disease: 1.More male than female. 2.Never pass form father to son (son only get Y from father). 3.Maternal father pass the disease to grandson. 4.The disease often skip one generation from grandfather through a carrier daughter. 5.With the rare affected female, all her son will be affected and all her daughter will be carriers.

28. 性聯遺傳低磷酸佝僂症 1. More female than male have the disease 2. Father to daughter 3. 50% of son and daughter

29. Sex-limited trait: Affect a structure or process that is found in one sex but not the other. Sex-influenced traits: Show up in both sex, but expression of this trait differ between two sex because of hormone difference - pattern baldness