The Father of Genetics – Gregor Johann Mendel (1822-1884)

2. The Father of Genetics – Gregor Johann Mendel (1822-1884) • 1863 - 1866 • Mendel cultivated and tested some 28 000 pea plants

3. Allele – Different form of a gene • Dominant allele - In a heterozygote, the allele that is fully expressed in the phenotype. • Recessive allele - In a heterozygote, the allele that is completely masked in the phenotype. • Phenotype – The outward appearance of a trait • Genotype – The combination of alleles (Letters)

4. Mendel’s Experiments • Used 34 "true-breeding" strains of the common garden pea plant • These strains differed from each other in very pronounced (visible) ways so that there could be no doubt as the results of a given experiment. • Pea plants were perfect for such experiments since their flowers had both male (anthers) and female (pistils) flower parts • The flower petals never open therefore no foreign pollen could enter and back crosses (self fertilization) was easy.

6. Flower Parts

7. Principles of Dominance Section 11-1 P Generation F1 Generation F2 Generation Tall Short Tall Tall Tall Tall Tall Short

8. Principles of Dominance Section 11-1 P Generation F1 Generation F2 Generation Tall Short Tall Tall Tall Tall Tall Short

9. Principles of Dominance Section 11-1 P Generation F1 Generation F2 Generation Tall Short Tall Tall Tall Tall Tall Short

10. Figure 11-3 Mendel’s Seven F1 Crosses on Pea Plants Section 11-1 Seed Shape Seed Color Seed Coat Color Pod Shape Pod Color Flower Position Plant Height Round Yellow Gray Smooth Green Axial Tall Wrinkled Green White Constricted Yellow Terminal Short Round Yellow Gray Smooth Green Axial Tall

11. Section Outline Section 11-2 • 11–2 Probability and Punnett Squares A. Genetics and Probability B. Punnett Squares C. Probability and Segregation D. Probabilities Predict Averages

12. Tt X Tt Monohybrid Cross Section 11-2

13. Tt X Tt Cross Section 11-2

14. Monohybrid Cross Phenotypes

15. Law of Segregation

16. Section Outline Section 11-3 • 11–3 Exploring Mendelian Genetics A. Independent Assortment 1. The Two-Factor Cross: F1 2. The Two-Factor Cross: F2 B. A Summary of Mendel’s Principles C. Beyond Dominant and Recessive Alleles 1. Incomplete Dominance 2. Codominance 3. Multiple Alleles 4. Polygenic Traits D. Applying Mendel’s Principles E. Genetics and the Environment

17. Alleles are separated during gamete formation Some alleles dominant, & some alleles recessive “Factors” determine traits Pea plants Law of Dominance Law of Segregation Concept Map Section 11-3 Gregor Mendel concluded that experimented with which is called the which is called the

18. Figure 11-10 Independent Assortment in Peas Section 11-3

19. Dihybrid Cross Section 11-2

20. Figure 11-11 Incomplete Dominance in Four O’Clock Flowers Section 11-3

21. Figure 11-11 Incomplete Dominance in Four O’Clock Flowers Section 11-3

22. Section Outline Section 11-4 • 11–4 Meiosis A. Chromosome Number B. Phases of Meiosis 1. Meiosis I 2. Meiosis II C. Gamete Formation D. Comparing Mitosis and Meiosis

23. Homologous Chromosome

24. Crossing-Over Section 11-4

25. Crossing-Over Section 11-4

26. Crossing-Over Section 11-4

28. Figure 11-15 Meiosis Section 11-4 Meiosis I

29. Figure 11-15 Meiosis Section 11-4 Meiosis I Meiosis I

30. Figure 11-15 Meiosis Section 11-4 Meiosis I Meiosis I

31. Figure 11-15 Meiosis Section 11-4 Meiosis I

32. Figure 11-15 Meiosis Section 11-4 Meiosis I

33. Figure 11-17 Meiosis II Section 11-4 Meiosis II Prophase II Metaphase II Anaphase II Telophase II Meiosis I results in two haploid (N) daughter cells, each with half the number of chromosomes as the original. The chromosomes line up in a similar way to the metaphase stage of mitosis. The sister chromatids separate and move toward opposite ends of the cell. Meiosis II results in four haploid (N) daughter cells.

34. Figure 11-17 Meiosis II Section 11-4 Meiosis II Prophase II Metaphase II Anaphase II Telophase II Meiosis I results in two haploid (N) daughter cells, each with half the number of chromosomes as the original. The chromosomes line up in a similar way to the metaphase stage of mitosis. The sister chromatids separate and move toward opposite ends of the cell. Meiosis II results in four haploid (N) daughter cells.

35. Figure 11-17 Meiosis II Section 11-4 Meiosis II Prophase II Metaphase II Anaphase II Telophase II Meiosis I results in two haploid (N) daughter cells, each with half the number of chromosomes as the original. The chromosomes line up in a similar way to the metaphase stage of mitosis. The sister chromatids separate and move toward opposite ends of the cell. Meiosis II results in four haploid (N) daughter cells.

36. Figure 11-17 Meiosis II Section 11-4 Meiosis II Prophase II Metaphase II Anaphase II Telophase II Meiosis I results in two haploid (N) daughter cells, each with half the number of chromosomes as the original. The chromosomes line up in a similar way to the metaphase stage of mitosis. The sister chromatids separate and move toward opposite ends of the cell. Meiosis II results in four haploid (N) daughter cells.

37. Figure 11-17 Meiosis II Section 11-4 Meiosis II Prophase II Metaphase II Anaphase II Telophase II Meiosis I results in two haploid (N) daughter cells, each with half the number of chromosomes as the original. The chromosomes line up in a similar way to the metaphase stage of mitosis. The sister chromatids separate and move toward opposite ends of the cell. Meiosis II results in four haploid (N) daughter cells.

38. Genetic Recombination

39. Interest Grabber Section 11-5 Forever Linked? • Some genes appear to be inherited together, or “linked.” If two genes • are found on the same chromosome, does it mean they are linked forever? • Study the diagram, which shows four genes labeled A–E and a–e, and then answer the questions on the next slide.

40. Interest Grabber continued Section 11-5 • 1. In how many places can crossing over result in genes A and b being on the same chromosome? • 2. In how many places can crossing over result in genes A and c being on the same chromosome? Genes A and e? • 3. How does the distance between two genes on a chromosome affect the chances that crossing over will recombine those genes?

41. Section Outline Section 11-5 • 11–5 Linkage and Gene Maps A. Gene Linkage B. Gene Maps

42. Comparative Scale of a Gene Map Section 11-5 Mapping of Earth’s Features Mapping of Cells, Chromosomes, and Genes Cell Earth Chromosome Country Chromosome fragment State Gene City People Nucleotide base pairs

43. Figure 11-19 Gene Map of the Fruit Fly Section 11-5 Exact location on chromosomes Chromosome 2

44. Video 1 Video 1 Meiosis Overview • Click the image to play the video segment.

45. Video 2 Video 2 Animal Cell Meiosis, Part 1 • Click the image to play the video segment.

46. Video 3 Video 3 Animal Cell Meiosis, Part 2 • Click the image to play the video segment.

47. Video 4 Video 4 Segregation of Chromosomes • Click the image to play the video segment.

48. Video 5 Video 5 Crossing Over • Click the image to play the video segment.

49. Interest Grabber Answers Section 5 Answers • 1. In how many places can crossing over result in genes A and b being on the same chromosome? • One (between A and B) • 2. In how many places can crossing over result in genes A and c being on the same chromosome? Genes A and e? • Two (between A and B and A and C); Four (between A and B, A and C, A and D, and A and E) • 3. How does the distance between two genes on a chromosome affect the chances that crossing over will recombine those genes? • The farther apart the genes are, the more likely they are to be recombined through crossing over.