2. Biology I - GENETICS 1-12 Novak

3. Gregor Mendel 1822-1884

7. MENDEL’S PRINCIPLES

8. I. ALLELES Any organism has two units of heredity (genes) for each trait in every body cell

9. II. SEGREGATION The two units (genes) for a trait are separated in the cell; one gene is found on a chromosome while the other is located in the same place on its partner (homologous) chromosome

11. III. DOMINANCE A. When two genes of a trait are different in the cells of the organism, the gene that shows up is the dominant while the gene that remains hidden is the recessive B. Combinations of the two genes (genotypes) 1. Homozygous (pure) dominant - both genes are dominant 2. Homozygous (pure) recessive - both genes are recessive 3. Heterozygous (hybrid) - one gene is dominant & the other is recessive

12. IV. RECOMBINATION - (INDEPENDENT ASSORTMENT) In each new generation there is a complete new rearrangement of the units of heredity (genes)

14. Following the Generations Cross 2 Pure Plants TT x tt Results in all Hybrids Tt Cross 2 Hybrids get 3 Tall & 1 Short TT, Tt, tt

15. Generation “Gap” Parental P 1 Generation = the parental generation in a breeding experiment.Parental P 1 Generation = the parental generation in a breeding experiment. F 1 generation = the first-generation offspring in a breeding experiment. (1st filial generation)F 1 generation = the first-generation offspring in a breeding experiment. (1st filial generation) –From breeding individuals from the P 1 generation F 2 generation = the second-generation offspring in a breeding experiment. (2nd filial generation)F 2 generation = the second-generation offspring in a breeding experiment. (2nd filial generation) – From breeding individuals from the F 1 generation

16. Mendel’s Experimental Results

17. Thomas Hunt Morgan 1866-1945

22. Incomplete Dominance (blending inheritance)

23. INCOMPLETE DOMINANCE A condition in which both alleles for a characteristic are partially expressed

24. Incomplete Dominance F1 hybrids in betweenphenotypesF1 hybrids have an appearance somewhat in between or a blend of the phenotypes of the two parental varieties. Example:snapdragons (flower)Example: snapdragons (flower) red (RR) x white (WW) R = red flowerR = red flower W = white flower W W RR

25. Incomplete Dominance RWRWRWRW RR All RW = pink (heterozygous pink) produces the F 1 generation W W

26. Incomplete Dominance

27. CODOMINANCE A condition in which both alleles for a characteristic are fully expressed

28. Codominant white and pink

30. Homozygous Red

31. Hereford Red

32. Homozygous white

33. Roan hybrid

35. Codominant cross

36. Sex-Linked Inheritance

38. Color Blindness

39. normal - trichromatic color vision protanopia red-green blindness (no red cones) deutanopia red-green blindness (no green cones) tritanopia blue-yellow blindness (no blue cones) typical achromatopsia (no cones; rod monochromat) protanomaly (anomalous red cones) deutanomaly (anomalous green cones) tritanomaly (anomalous blue cones) atypical achromatopsia (low cones; cone monochromat) TYPES OF COLOR BLINDNESS

40. Red Green Color Blindness Male1.01% Female0.02%

44. Sex-linked Traits Traits (genes) located on the sex chromosomesTraits (genes) located on the sex chromosomes Sex chromosomes are X and YSex chromosomes are X and Y XX genotype for femalesXX genotype for females XY genotype for malesXY genotype for males Many sex-linked traits carried on X chromosomeMany sex-linked traits carried on X chromosome

49. Hemophilia

50. Female Carriers

51. The effects of hemophilia

54. Human Blood Coagulation Cascade

57. DIHYBRID INHERITANCE

58. Pea Plants Tall = TT, Tt Short = tt Height Seed Color Yellow = YY, Yy Green = yy Let’s cross a homozygous tall (TT), homozygous yellow seed (YY) plant with a short (tt), green seed (yy) plant. TTYY x ttyy These are the genotypes of the two plants.

59. Independent Assortment Mendels’ principle of Independent Assortment states that genes for different traits can segregate independently during the formation of gametes (eggs & sperm in animals, eggs and pollen in plants). TTYY T Y First Twith first Y Gamete 1 = sperm, egg, pollen...

60. Independent Assortment Mendels’ principle of Independent Assortment states that genes for different traits can segregate independently during the formation of gametes (eggs & sperm in animals, eggs and pollen in plants). TTYY TY TY First Twith second Y Gamete 1 Gamete 2

61. Independent Assortment Mendels’ principle of Independent Assortment states that genes for different traits can segregate independently during the formation of gametes (eggs & sperm in animals, eggs and pollen in plants). TTYY TY TY Second Twith first Y Gamete 1 Gamete 2Gamete 3

62. Independent Assortment Mendels’ principle of Independent Assortment states that genes for different traits can segregate independently during the formation of gametes (eggs & sperm in animals, eggs and pollen in plants). TTYY TY YT Second Twith second Y Gamete 1 Gamete 2Gamete 3Gamete 4

63. Dihybrid Punnett Square - F1 TY ty P1 = TTYY P2 = ttyy Will be F1 Generation

64. Dihybrid Punnett Square - F1 TY tyTTYyTTYy TTYyTTYy TTYyTTYy TTYyTTYy

65. Dihybrid Punnett Square - F1 TY tyTtYyTtYyTtYyTtYyTtYyTtYyTtYy tyTTYYTTYYTtYY TTYY tyTTYYTTYYTTYY tyTTYYTTYYTTYY

66. Dihybrid Punnett Square - F1 TY tyTtYy tyTtYy tyTtYy tyTtYy

67. Dihybrid Punnett Square - F1 TY tyTtYy tyTtYy tyTtYy tyTtYy Genotype ratio: TtYy - 16/16 Phenotype ratio: Tall, Yellow - 16/16

68. Dihybrid Punnett Square – F2 We need to pair up the genes which can be given to each gamete (egg and pollen). Let’s cross two of the plants from the F 1 generation TY tyTtYy tyTtYy tyTtYy tyTtYy x. T YTytYyt We need to pair up the genes

69. Dihybrid Punnett Square F2 TYTytYty TY Ty tY ty Both the plants can give the same gene combinations to their gametes, so the pairs along the top and down the side are the same.

70. Dihybrid Punnett Square – F2 When you pair up the gametes from the two plants, always put like letters together and within the like letters, put the CAPITAL letter in front of the lowercase letter.

71. Dihybrid Punnett Square F2 TYTytYty TYTTYYTTYyTtYYTtYy Ty???? tY???? ty???? Your Turn!!

72. Dihybrid Punnett Square F2 TYTytYty TYTTYYTTYyTtYYTtYy TyTTYyTTyyTtYyTtyy tYTtYYTtYyttYYttYy tyTtYyTtyyttYyttyy F 2 generation

73. Dihybrid Punnett Square F2 TYTytYty TYTTYYTTYyTtYYTtYy TyTTYyTTyyTtYyTtyy tYTtYYTtYyttYYttYy tyTtYyTtyyttYyttyy Genotype and phenotype ratios?

74. F2 Genotype Ratio TTYY - 1 TTYy - 2 TtYY - 2 TtYy - 4 TTyy - 1 Ttyy - 2 ttYY - 1 ttYy - 2 ttyy - 1

75. F2 Phenotype Ratio TTYY - 1 TTYy - 2 TtYY - 2 TtYy - 4 TTyy - 1 Ttyy - 2 ttYY - 1 ttYy - 2 ttyy - 1 Tall, Yellow - 9 Tall, Green - 3 Short, Yellow - 3 Short, Green - 1

76. Another Mendelian Dihybrid Problem

79. Dihybrid F2 Results

81. The End