1. Mendel’s Laws 1. Law of Dominance 2. Law of Segregation
3. Law of Independent Assortment

2. Law of Dominance
Offspring that are hybrid for a trait will have only the dominant trait in the phenotype.
Parent Pea Plant
F1 Pea Plants
tall stem x short stem
all tall stems
yellow seeds x green seeds
all yellow seeds
green pea pods x yellow pea pods
all green pea pods
round seeds x wrinkled seeds
all round seeds

3. The Law of Segregation
During the formation of gametes (eggs or sperm), the two alleles responsible for a trait separate from each other.  Alleles for a trait are then "recombined" at fertilization, producing the genotype for the traits of the offspring.

4. The Law of Segregation
Now, when completing a Punnet Square, we model this "Law of Segregation" every time.  When you "split" the genotype letters & put one above each column & one in front of each row, you have SEGREGATED the alleles for a specific trait. In real life this happens during a process of cell division called "MEIOSIS". 

5. Law of Independent Assortment
Alleles for different traits are distributed to sex cells (& offspring) independently of one another. The different traits do not influence the inheritance of each other.  They are inherited INDEPENDENTLY. Height (tall or short), seed shape (round or wrinkled), pod color (green or yellow), etc.  Mendel noticed during all his work that the height of the plant and the shape of the seeds and the color of the pods had no impact on one another.  In other words, being tall didn't automatically mean the plants had to have green pods, nor did green pods have to be filled only with wrinkled seeds, the different traits seem to be inherited INDEPENDENTLY.

6. Complete Dominance
The dominant alleles covers up (masks) the recessive allele.
R = round r = wrinkled
Rr = Round (the round allele hides the wrinkled allele)

7. Complete Dominance R r RR Rr R r Rr rr Trait: Seed Shape
Alleles: R – Round r – Wrinkled
Cross: Round seeds x Round seeds
Rr x Rr R r
Genotype: RR, Rr, rr
Phenotype: Round & wrinkled
G.Ratio: 1:2:1
P.Ratio: 3:1 RR Rr R r Rr rr

8. Complex Inheritance

9. Types of Complex Inheritance
Incomplete Dominance
Codominance
Multiple Alleles
Polygenic Traits

10. Incomplete dominance Both alleles partially show by blending together
Analogy: Mixing Together Paint
Blue
Green
Yellow

11. r r w r w r w w r w r w Incomplete dominance Homozygous Dominant
Recessive

12. Incomplete dominance
100% pink offspring r r w r w r w w r w r w

13. Incomplete dominance
Heterozygous r w r r r r w w r w w w
Heterozygous

14. Incomplete dominance
Heterozygous r w r r r r w w r w w w
Heterozygous

15. R r R r Incomplete dominance
Heterozygous
A 1:2:1 ratio with 25% red, 50% pink & 25% white offspring R r R r
Heterozygous

16. Both alleles are completely expressed at the same time.
codominance
Both alleles are completely expressed at the same time.
-Analogy: Mixing Together Pebbles
Yellow AND Blue
Yellow
Blue

18. codominance

19. review
Dominance

20. Review
Incomplete dominance

21. Review
codominance

22. Multiple alleles Having more than two alleles for a specific trait
Ex. An example is blood groups in humans. Blood type, for example, is determined by three alleles.
A is codominant
B is codominant
O is recessive

23. Blood Types Alleles (Genotype) Blood Type (Phenotype) AA or Ao Type A
BBor Bo
Type B
AB only
Type AB
oo only
Type O

25. Polygenic Traits
Traits that are determined by the interaction of multiple pairs of genes
Ex: skin color, height

26. Incomplete and Codominance
a) Birds can be blue, white, or white with blue-tipped feathers.
b) Flowers can be white, pink, or red.
c) A Hoo can have curly hair, spiked hair, or a mix of both curly and spiked.
d) A Sneech can be tall, medium, or short.
e) A Bleexo can be spotted, black, or white.

27. Incomplete and Codominance
a) Birds can be blue, white, or white with blue-tipped feathers.
BB = blue WW = white BW = blue-tipped
b) Flowers can be white, pink, or red.
c) A Hoo can have curly hair, spiked hair, or a mix of both curly and spiked.
d) A Sneech can be tall, medium, or short.
e) A Bleexo can be spotted, black, or white.

28. Incomplete and Codominance
a) Birds can be blue, white, or white with blue-tipped feathers.
BB = blue WW = white BW = blue-tipped
b) Flowers can be white, pink, or red.
RR = red WW = white RW = pink
c) A Hoo can have curly hair, spiked hair, or a mix of both curly and spiked.
d) A Sneech can be tall, medium, or short.
e) A Bleexo can be spotted, black, or white.

29. Incomplete and Codominance
a) Birds can be blue, white, or white with blue-tipped feathers.
BB = blue WW = white BW = blue-tipped
b) Flowers can be white, pink, or red.
RR = red WW = white RW = pink
c) A Hoo can have curly hair, spiked hair, or a mix of both curly and spiked.
CC = curly SS = spiked CS = mixture
d) A Sneech can be tall, medium, or short.
e) A Bleexo can be spotted, black, or white.

30. Incomplete and Codominance
a) Birds can be blue, white, or white with blue-tipped feathers.
BB = blue WW = white BW = blue-tipped
b) Flowers can be white, pink, or red.
RR = red WW = white RW = pink
c) A Hoo can have curly hair, spiked hair, or a mix of both curly and spiked.
CC = curly SS = spiked CS = mixture
d) A Sneech can be tall, medium, or short.
TT = tall SS = short TS = medium
e) A Bleexo can be spotted, black, or white.

31. Incomplete and Codominance
a) Birds can be blue, white, or white with blue-tipped feathers.
BB = blue WW = white BW = blue-tipped
b) Flowers can be white, pink, or red.
RR = red WW = white RW = pink
c) A Hoo can have curly hair, spiked hair, or a mix of both curly and spiked.
CC = curly SS = spiked CS = mixture
d) A Sneech can be tall, medium, or short.
TT = tall SS = short TS = medium
e) A Bleexo can be spotted, black, or white.
BB = black WW = white BW = spotted

32. 2. Now, can you figure out in the above list, which of the letters represent codominant traits and which are incomplete. A. B. C. D. E.

33. 2. Now, can you figure out in the above list, which of the letters represent codominant traits and which are incomplete.
A. Codominance B. C. D. E.

34. B. Incomplete Dominance C. D. E.
2. Now, can you figure out in the above list, which of the letters represent codominant traits and which are incomplete.
A. Codominance
B. Incomplete Dominance C. D. E.

35. B. Incomplete Dominance C. Codominance D. E.
2. Now, can you figure out in the above list, which of the letters represent codominant traits and which are incomplete.
A. Codominance
B. Incomplete Dominance
C. Codominance D. E.

36. B. Incomplete Dominance C. Codominance D. Incomplete Dominance E.
2. Now, can you figure out in the above list, which of the letters represent codominant traits and which are incomplete.
A. Codominance
B. Incomplete Dominance
C. Codominance
D. Incomplete Dominance E.

37. B. Incomplete Dominance C. Codominance D. Incomplete Dominance
2. Now, can you figure out in the above list, which of the letters represent codominant traits and which are incomplete.
A. Codominance
B. Incomplete Dominance
C. Codominance
D. Incomplete Dominance
E. Codominance

38. In some chickens, the gene for feather color is controlled by codominance. The allele for black is B and the allele for white is W. The heterozygous phenotype is known as erminette.
a. What is the genotype for black chickens?
b. What is the genotype for white chickens? c. What is the genotype for erminette chickens?

39. In some chickens, the gene for feather color is controlled by codominance. The allele for black is B and the allele for white is W. The heterozygous phenotype is known as erminette.
a. What is the genotype for black chickens? BB
b. What is the genotype for white chickens? c. What is the genotype for erminette chickens?

40. In some chickens, the gene for feather color is controlled by codominance. The allele for black is B and the allele for white is W. The heterozygous phenotype is known as erminette.
a. What is the genotype for black chickens? BB
b. What is the genotype for white chickens? WW c. What is the genotype for erminette chickens?

41. In some chickens, the gene for feather color is controlled by codominance. The allele for black is B and the allele for white is W. The heterozygous phenotype is known as erminette.
a. What is the genotype for black chickens? BB
b. What is the genotype for white chickens? WW c. What is the genotype for erminette chickens? BW

42. If two erminette chickens were crossed, what is the probability that:
They would have a black chick? ____%
They would have a white chick? ____%

43. If two erminette chickens were crossed, what is the probability that:
They would have a black chick? ____%
They would have a white chick? ____%
BW x BW B W B W

44. If two erminette chickens were crossed, what is the probability that:
They would have a black chick? 25%
They would have a white chick? 25%
BW x BW B W BB BW WW B W

45. A black chicken and a white chicken are crossed.
What is the probability that they will have erminette chicks? ____%

46. A black chicken and a white chicken are crossed.
What is the probability that they will have erminette chicks? ____%
BB x WW B B W W

47. A black chicken and a white chicken are crossed.
What is the probability that they will have erminette chicks? 100%
BB x WW B B BW W W

48. In snapdragons, flower color is controlled by incomplete dominance
In snapdragons, flower color is controlled by incomplete dominance. The two alleles are red (r) and white (w). The heterozygous genotype is expressed as pink.
a. What is the phenotype of a plant with the genotype rr? ___________
b. What is the phenotype of a plant with the genotype ww? ___________
c. What is the phenotype of a plant with the genotype rw? ___________

49. In snapdragons, flower color is controlled by incomplete dominance
In snapdragons, flower color is controlled by incomplete dominance. The two alleles are red (R) and white (W). The heterozygous genotype is expressed as pink.
a. What is the phenotype of a plant with the genotype RR? Red
b. What is the phenotype of a plant with the genotype WW? ___________
c. What is the phenotype of a plant with the genotype RW? ___________

50. In snapdragons, flower color is controlled by incomplete dominance
In snapdragons, flower color is controlled by incomplete dominance. The two alleles are red (R) and white (W). The heterozygous genotype is expressed as pink.
a. What is the phenotype of a plant with the genotype RR? Red
b. What is the phenotype of a plant with the genotype WW? White
c. What is the phenotype of a plant with the genotype RW? ___________

51. In snapdragons, flower color is controlled by incomplete dominance
In snapdragons, flower color is controlled by incomplete dominance. The two alleles are red (R) and white (W). The heterozygous genotype is expressed as pink.
a. What is the phenotype of a plant with the genotype RR? Red
b. What is the phenotype of a plant with the genotype WW? White
c. What is the phenotype of a plant with the genotype RW? Pink

52. A pink-flowered plant is crossed with a white-flowered plant.
What is the probability of producing a pink-flowered plant? ____%

53. A pink-flowered plant is crossed with a white-flowered plant.
What is the probability of producing a pink-flowered plant? ____%
RW x WW R W W W

54. A pink-flowered plant is crossed with a white-flowered plant.
What is the probability of producing a pink-flowered plant?
50%
RW x WW R W RW WW W W

55. Multiple Allele Traits: Blood Type
Blood type exhibits codominance and multiple alleles. The chart below shows the phenotype and genotype of blood types.
Phenotype Genotype
Type A AA or Ao
Type B BB or Bo
Type AB AB
Type O oo
Blood Type is controlled by 3 alleles: A, B, O. A & B are codominant, O is recessive.

56. 1. a) What are the two genotypes possible for a person who as A blood
b) What genotype does a person with AB blood have? _______________
c ) What genotype does a person with O blood have? _____________ d) What are the two genotypes possible for a person who as B blood? ___________

57. 1. a) What are the two genotypes possible for a person who as A blood
1. a) What are the two genotypes possible for a person who as A blood? AA or Ao
b) What genotype does a person with AB blood have? _______________
c ) What genotype does a person with O blood have? _____________ d) What are the two genotypes possible for a person who as B blood? ___________

58. 1. a) What are the two genotypes possible for a person who as A blood
1. a) What are the two genotypes possible for a person who as A blood? AA or Ao
b) What genotype does a person with AB blood have? AB
c ) What genotype does a person with O blood have? _____________ d) What are the two genotypes possible for a person who as B blood? ___________

59. 1. a) What are the two genotypes possible for a person who as A blood
1. a) What are the two genotypes possible for a person who as A blood? AA or Ao
b) What genotype does a person with AB blood have? AB
c ) What genotype does a person with O blood have? oo d) What are the two genotypes possible for a person who as B blood? ___________

60. 1. a) What are the two genotypes possible for a person who as A blood
1. a) What are the two genotypes possible for a person who as A blood? AA or Ao
b) What genotype does a person with AB blood have? AB
c ) What genotype does a person with O blood have? oo d) What are the two genotypes possible for a person who as B blood? BB or Bo

61. 2. A man with type AB blood is married to a woman also with type AB blood.
What blood types will their children have and in what proportion?

62. AB x AB
2. A man with type AB blood is married to a woman also with type AB blood.
What blood types will their children have and in what proportion? A B A B

63. 2. A man with type AB blood is married to a woman also with type AB blood.
What blood types will their children have and in what proportion?
¼ Type A
½ Type AB
¼ Type B
AB x AB A B AA AB BB A B

64. 3. A man has type B blood (genotype BB) is married to a woman with type O blood.
What blood type will all of their children have? _______________
What is the genotype of the children? _____________

65. BB x oo
3. A man has type B blood (genotype BB) is married to a woman with type O blood.
What blood type will all of their children have? _______________
What is the genotype of the children? _____________ B B O O

66. BB x oo
3. A man has type B blood (genotype BB) is married to a woman with type O blood.
What blood type will all of their children have? Type B
What is the genotype of the children? Bo B B Bo O O

67. 4. A woman with type A blood (genotype AO) is married to a type B person (genotype BO). What proportion of their children with have:
A blood? _______
B blood? _____
O blood? _______.

68. Ao x Bo
4. A woman with type A blood (genotype AO) is married to a type B person (genotype BO). What proportion of their children with have:
A blood? _______
B blood? _____
O blood? _______. A O B O

69. Ao x Bo
4. A woman with type A blood (genotype AO) is married to a type B person (genotype BO). What proportion of their children with have:
A blood? ¼
B blood? ¼
O blood? ¼ A O AB BO AO OO B O

70. A woman with type A blood is claiming that a man with type AB blood is the father of her child who is also type AB.
Could this man be the father of the child? __________
Show the possible crosses; remember that the woman can have AA or AO genotypes.

71. A A
A woman with type A blood is claiming that a man with type AB blood is the father of her child who is also type AB.
Could this man be the father of the child? __________
Show the possible crosses; remember that the woman can have AA or AO genotypes. A B A O A B

72. A AA AB A B A O AA AO AB BO A B A
A woman with type A blood is claiming that a man with type AB blood is the father of her child who is also type AB.
Could this man be the father of the child? YES
Show the possible crosses; remember that the woman can have AA or AO genotypes. AA AB A B A O AA AO AB BO A B

73. 6. A man with type AB blood is married to a woman with type O blood
6. A man with type AB blood is married to a woman with type O blood. They have two natural children and one adopted child. Jane has type A blood, Bobby has type B blood, and Grace has type O blood. Which child was adopted? _________________

74. AB X OO A B
6. A man with type AB blood is married to a woman with type O blood. They have two natural children and one adopted child. Jane has type A blood, Bobby has type B blood, and Grace has type O blood. Which child was adopted? _________________ O O

75. AB X OO A B
6. A man with type AB blood is married to a woman with type O blood. They have two natural children and one adopted child. Jane has type A blood, Bobby has type B blood, and Grace has type O blood. Which child was adopted? Grace AO BO O O

76. 7. A heterozygous type B man and a type AB woman want to have a child.
a. What are the chances that they will have a type B child? _______
b. What are the chances that their child will be a type O? ________
c. Other than a blood type B, what other blood types could their child have? ____
d. The child is type AB. Could this child be from the man and woman? __________

77. Bo x AB B O
7. A heterozygous type B man and a type AB woman want to have a child.
a. What are the chances that they will have a type B child? _______
b. What are the chances that their child will be a type O? ________
c. Other than a blood type B, what other blood types could their child have? ____
d. The child is type AB. Could this child be from the man and woman? __________ A B

78. Bo x AB B O
7. A heterozygous type B man and a type AB woman want to have a child.
a. What are the chances that they will have a type B child? %
b. What are the chances that their child will be a type O? 0 %
c. Other than a blood type B, what other blood types could their child have? Type AB or A
d. The child is type AB. Could this child be from the man and woman? yes AB Ao BB Bo A B

79. A type AB man and type O woman decide to have a child.
What are the chances that they will have a type O baby? ________
What are the chances that their second child will have type B blood? __________

80. AB X oo A B O O A type AB man and type O woman decide to have a child.
What are the chances that they will have a type O baby? ________
What are the chances that their second child will have type B blood? __________ A B O O

81. AB X oo
A type AB man and type O woman decide to have a child.
What are the chances that they will have a type O baby? %
What are the chances that their second child will have type B blood? % A B Ao Bo O O

82. 9. A type A woman and a type B man have a type O child.
a. What was the genotype of the man? _______
b. What was the genotype of the woman? ________
c. What are the chances that this couple will have a type AB child? ________

83. A? X B? A
9. A type A woman and a type B man have a type O child.
a. What was the genotype of the man? _______
b. What was the genotype of the woman? ________
c. What are the chances that this couple will have a type AB child? ________ ? AB B? A? ?? B ?

84. A? X B? A
9. A type A woman and a type B man have a type O child.
a. What was the genotype of the man? Bo
b. What was the genotype of the woman? Ao
c. What are the chances that this couple will have a type AB child? 25% O AB Bo Ao oo B O