1. Mendelian Patterns of Inheritance
Chapter 11

2. QOD: c i e d b h f a g

3. Genetics: the study of heredity
Sexual Reproduction and Genetics
Ch 11
Genetics: the study of heredity
Heredity: the passing of traits to the next generation. (from parent to child)
Trait: a physical feature (blue eyes)

4. Dominant trait: a trait that always shows, can cover the other allele.
- represented by a Capital letter
EX: Brown eye: B
Recessive trait: a trait that only shows of both alleles are present.
- represented by lower case letter
EX: blue eye: b

5. Codominant: both alleles are expressed (shown) .
EX: Bb: Brown (B) and Blue (b) eyes are both expressed

6. Homozygous: two of the same alleles for a particular trait
Sexual Reproduction and Genetics
Homozygous: two of the same alleles for a particular trait
ex: BB or bb also called pure
Homozygous:
Heterozygous: two different alleles for a particular trait
Ex: Bb also called hybrid
Heterozygous
Gregor Mendel: the father of genetics,
studies the traits of pea plants

8. 11.1 Gregor Mendel “Father of Genetics”
Developed the fundamental laws of heredity 
He studied science and mathematics 
-chose to study genetics in garden peas (Pisum sativum)as as they are easily grown and their pollination is easily controlled. He controlled pollination by manually moving pollen between plants Developed True-breeding plants by self-pollination 
Funfact: Mendel originally wanted to breed mice, but wasn't allowed to because it was considered scandalous

9. Mendel examined varieties of peas for heritable characters and traits for his study. (stem length, pod shape, seed shape, seed color..etc) 
Developed hybrid plants by crossbreeding two plants of differing characteristics
Tall v Short

10. P generation F1 F2 Mendel offspring 2 offspring 1 parents grandkids
Sexual Reproduction and Genetics
Mendel
P generation F1 F2
offspring 1
kids
offspring 2
grandkids
parents

11. 11.2 Mendel's Law of Segregation (MONOHYBRID CROSS)
A monohybrid cross involves one (mono) character and different (hybrid) traits.
The F1 seeds were all purple; the white flower trait failed to appear at all.
Because the purple flower trait completely masks the white flower trait when true-breeding plants are crossed, the purple flower trait is called dominant, and the white flower trait is called recessive.

12. Creating the F2 generation
*Cross the F1 generation together to create F2
*Ratio is always 3:1
Mendel proposed that the units responsible for inheritance were discrete particles - particulate theory of inheritance

13. In 1865, Mendel published his findings in a paper called Experiments on Plant Hybridization, which was mostly ignored at the time due to a number of reasons. First, Mendel was not well known in scientific community. Second, his theory ran against the popular model of blended inheritance.

14. As Viewed by Modern Genetics
During production of gametes, only one of the pair members for a given parent passes to the gamete. (LAW OF SEGREGATION)
Mendel's units of inheritance are now called genes.
Different forms of a gene are called alleles.
Each allele is given a symbol:
                                                                                                           
Parental Cross 
PP  x  pp
purple x white

15. Mendel’s Three Laws 1. Dominance & Recessiveness
2. Segregation: the two alleles for a trait separate (or segregate) during the formation of gametes
 3. Independent Assortment: during gamete formation, alleles pair independently, meaning a particular allele for one character can be paired with either allele of another character

16.  Two copies of same allele = homozygous. Homo means "the same" 
Therefore both PP and pp are considered homozygous, just one is purple and the other is white.
Some purple-flowered plants could be Pp.  Individuals that are purple, but had a white parent, are heterozygous: Pp. Hetero means "different".
The F1 cross
Pp  x Pp   
purple x purple

17. Review Terms F1 vs F2 True Breeding vs Hybrid
Self Pollination vs  Cross Pollination
Homozygous vs Heterozygous
Particulate Theory vs Blending Theory
Segregation

18. The physical appearance of an organism is its phenotype
The physical appearance of an organism is its phenotype. Purple-flowered would be a phenotype.
The actual composition of the organism's alleles for a gene is its genotype: Pp is a genotype.
GENOTYPE
PHENOTYPE
          Pp
       purple flowers
 rr
wrinkled seeds TT
tall tt
short
Organisms have many different genes some have thousands, and complex organisms have 10 times that number.

19. Okay Better (use H for hair) Short hair = SS HH Short hair = Ss Hh
BY CONVENTION:
The dominant trait is given a capitol letter, the lowercase of that same letter is the recessive trait.  DO NOT MIX LETTERS.  Pick one and stick to it.
Also, some letters are better than others.  Capital S looks a lot like a lowercase (s).  Pick a different letter...
    Okay                     Better (use H for hair)
Short  hair  = SS                 HH
Short hair = Ss                    Hh
Long hair = ss                     hh 
Steps to solving genetics problems
Key
Parents cross
Punnett Square
Genotype and ratio
Phenotype and ratio

20. Punnett Square: to predict outcome of offspring
Steps to solving genetics problems
Key
Parents cross
Punnett Square
Genotype and ratio
Phenotype and ratio
Cross heterozygous green pea (Gg) with heterozygous green pea plant (Gg). Yellow is recessive.
Key: GG: Gg: gg
green yellow
P = Gg x Gg
G g
Genotype: ¼ GG; 2/4 Gg; ¼ gg
Genotype ratio: 1:2:1
Phenotype: ¾ green; ¼ yellow
Phenotype ratio: 3:1
G GG Gg
g Gg gg F1

21. In dragons...
Wings are a dominant trait, but some dragons are born wingless.
1. If a wingless dragon is crossed with one that is heterozygous, how many of its offspring will also be wingless?
2. What are the chances that two heterozygous dragons have a whelp that is wingless?

22. If a wingless dragon is crossed with one that is heterozygous, how many of its offspring will also be wingless?
Key: FF: Ff: ff
wings wingless
P = ff x Ff
f f
Genotype: 2/4= ½ Ff; ½ ff
Genotype ratio: 1:1
Phenotype: ½ wing; ½ wingless
Phenotype ratio: 1:1
F Ff Ff
f ff ff F1

23. What is a test cross? Key: F= winged f=wingless
I can help you!  Let's have offspring!
Help, help!  I don't know what my genotype is!!
Am I Ff or FF?
Key:
F= winged
f=wingless

24. Practice with Punnett Squares
1.  A  round seeded plant (RR) is crossed with a wrinkle seeded plant (rr).  What are the phenotypes of the offspring?
2.  Two heterozygous purple flowered pea plants are crossed.  What are the phenotypes of their offspring and in what proportion?
3.  A plant with green seeds (yy) is crossed with a heterozygous plant.  What percentage of their offspring have yellow seeds?

25. Why does the punnett square work?
It all goes back to meiosis.. each side represents a sperm or egg.  The boxes filled out simply give you the statistical chance that a certain sperm will fertilize a certain egg. 
Probability: The chance that an event will occur
- It is a prediction, and it could be wrong.

26. Mendel’s Laws of Probability
Can use probability and math to solve genetic problems.
Ex: If two parents are heterozygous for nostril flaring.
P= Ee X Ee
Chance of E =½
Chance of e = ½
Chance of EE = ½ x ½ = ¼
Chance of Ee = ½ x ½ = ¼
Chance of eE = ½ x ½ = ¼ Ee= ¼ + ¼ = ½
Chance of ee = ½ x ½ = ¼

27. fF= 1 X ½ = ½ ff=1 x ½ = 1/2 Key: FF: Ff: ff wings wingless
If a wingless dragon is crossed with one that is heterozygous, how many of its offspring will also be wingless?
Key: FF: Ff: ff
wings wingless
P = ff x Ff
½ ½ ½ ½ 1
fF= 1 X ½ = ½
ff=1 x ½ = 1/2

28. Incomplete Dominance

29. Incomplete Dominance
Traits appear to "blend" in offspring
RR x WW
      RW  (pink)
Show:
Pink x Red
Pink x Pink
White x White

30. Figure 11.14
This illustrates another style of "letters" to denote genotypes
R1 and R2
Coloration in Rodents
Black x White = Gray
BB   x   WW  =  BW

31. Sickle Cell Trait in Humans
Genotypes  & Phenotypes
Pleiotropic Effect: a single mutant gene affects two or more seemingly unrelated traits
- Sickle cell shape, and resistant to malaria parasite

32. Prevalence of Malaria
In tropical Africa, where malaria is common:
homozygous dominant individuals die of malaria
homozygous recessive individuals die of sickle cell anemia
heterozygote carriers are relatively free of both
reproductive advantage
Prevalence of Sickle Cell Anemia
Pleiotropic Effect: a single mutant gene affects two or more seemingly unrelated traits

33. Codominance

34. ROAN COW -           What happens when you cross a white and a red cow?
Roan is codominant - both alleles R and W are expressed

35. What happens when two Roan Cows are Crossed?
R r
R RR Rr
r Rr rr

36. In Make believe flowers…….
Incomplete Dominance
Key: RR = red
Rr = purple (BLENDING)
rr = blue
CoDominance
Key: RR = red
Rr = red and blue (both are expressed)
rr = blue

37. Incomplete Dominance Key: BB= Brown Bb = Tan bb = White P = Bb x Bb
Ex: A brown bird crosses with a white one and all the offspring produced are tan. If these offspring were crossed and produced 16 birds, how many would be tan?
Key: BB= Brown
Bb = Tan
bb = White
Incomplete Dominance
P = Bb x Bb
B b
Genotype: ¼ BB; ½ Bb; ¼ bb
Genotype ratio: 1:2:1
Phenotype: ¼ Brown ; ½ Tan ; ¼ White
Phenotype ratio: 1:2:1
B BB Bb
b Bb bb F2
If these offspring produced 16 birds how many would be expected to be tan? 8

38. QOD: 1. What does INDEPENDENT ASSORTMENT mean?
In your own words, describe what it means with regard to Mendelian genetics.
2. Mendel would have never developed this law if he'd chosen traits located on the same chromosome. Why do you think that would have altered his results?

39. Dihybrid Cross

40. Mendel's Law of Independent Assortment – Illustrated by the DIHYBRID cross
law describes the outcome of dihybrid (two character) crosses, or hybrid crosses involving additional characters.
A dihybrid is an individual that is a double heterozygote (e.g., with the genotype RrYy - round seed, yellow seed).
What are the gametes that can be produced by this individual?

41. Dihybrid Cross: RrYy x RrYy
 Dihybrid Cross: RrYy x RrYy cross two traits at same time: remember independent assortment

42. P = TtBb x TtBb Pheno ratio: 9 : 3 : 3 : 1
Key: In pigs,
T = curly tail B =brown coat
t = straight tail b = white coat
Complete dominance Complete dominance
P = TtBb x TtBb
G TB, Tb , tB, tb X TB, Tb, tB, tb
Phenotype
9/16 curly tail & brown coat
3/16 curly tail & white coat
3/16 straight tail & brown coat
1/16 straight tail & white coat
Genotype:
1/16 TTBB
2/16 TTBb
2/16 TtBB
4/16 TtBb
1/16 TTbb
2/16 Ttbb
1/16 ttBB
2/16 ttBb
1/16 ttbb
TB, Tb , tB, tb TB Tb tB tb
TTBB
TTBb
TtBB
TtBb
TTbb
Ttbb
ttBB
ttBb
ttbb
Pheno ratio: 9 : 3 : 3 : 1

43. What percentage of the offspring will be hybrid for both traits?
Continued….
What percentage of the offspring will be purebred dominant for both traits?
1/16 or 6%
What percentage of the offspring will be hybrid for both traits?
4/16 or 25%
Genotype:
1/16 TTBB
2/16 TTBb
2/16 TtBB
4/16 TtBb
1/16 TTbb
2/16 Ttbb
1/16 ttBB
2/16 ttBb
1/16 ttbb
Phenotype
9/16 curly & brown
3/16 curly & white
3/16 straight & brown
1/16 straight & white
Key: In pigs,
T = curly tail B =brown coat
t = straight tail b = white coat

44. All of these type of crosses will follow the same ratio
AaBb x AaBb both heterozygous for both traits
(two dominant traits)
3 - (one dominant, one recessive)
3 - (one recessive, one dominant)
1 - (two recessive traits)

45. P = TTbb x ttbb Pheno ratio: 0 : 1 : 0 : 0 Key: In pigs, G Tb X tb 1b.
T = curly tail B =brown coat
t = straight tail b = white coat
Complete dominance Complete dominance
P = TTbb x ttbb
G Tb X tb
Phenotype
100% curly tail and white coat
Genotype:
100% Ttbb Tb tb
Ttbb
Pheno ratio: 0 : 1 : 0 : 0

46. P = Wwhh x WWHh Pheno ratio: 1 : 1 : 0 : 0 50%3.
Key: In Drosophila fruit flies
W = long wings H = hairless body
w = vestigial wings h = hairy body
Complete dominance Complete dominance
P = Wwhh x WWHh
G Wh, wh X WH, Wh
Genotype:
1/4 WWHh
1/4WwHh
1/4 WWhh
1/4 Wwhh
Phenotype
50% long wings and hairless body
50% long wings and hairy body
Wh wh WH Wh
WWHh
WwHh
WWhh
Wwhh
Pheno ratio: 1 : 1 : 0 : 0
What percentage of the offspring will have long wings and hairless bodies?
50%

47. P = LLgg x llGG Pheno ratio: 1 : 0 : 0 : 0 Key: In pea plants2.
Key: In pea plants
L = long stems G =green pods
l = short stems g = yellow pods
Complete dominance Complete dominance
P = LLgg x llGG
G Lg X lG Lg
Genotype:
100% LlGg
Phenotype:
100% long stems and green pods lG
LlGg
Pheno ratio: 1 : 0 : 0 : 0

48. How many off the offspring will be short haired and red eyed?
It may be faster to solve problems mathematically. This one is NOT 9:3:3:1
HhBb x hhBb
How many off the offspring will be short haired and red eyed?

49. Try another mathematical model..
Winged, Fire breathing dragon DdFf x
Wingless, Fire breathing dragon ddFf
Consider the cross between a plant with round seeds, purple flowers to one with wrinkled seeds and white flowers ...
RrPp x rrpp

50. Multiple Alleles

51. Multiple Alleles: more than two alleles in the population
Multiple Alleles: more than two alleles in the population ex: Blood Types  

52. Blood Type
There are 3 alleles that code for what type of blood you have. A, B, and O. A and B are Co-Dominant and O is recessive.
Phenotype Genotype Blood Donor % of population
Type A IAIA, IAiO Donate to Type A/AB %
Type B IBIB, IBiO Donate to Type B/AB 10%
Type AB IAIB Universal recipient/Donate to AB 4%
Type O iOiO Universal Donor/ only receive O 44%

53. Practice #1 P = AA x OO A A O AO AO O AO AO Genotype: Phenotype:
Cross: Type A (AA) father with a type 0 mother. What are the possible blood types of the offspring?
P = AA x OO
A A
O AO AO
O AO AO
Genotype:
Phenotype:
4/4 AO
4/4 Type A

54. Practice #3 A B O AO BO O AO BO BB, BO OO AB
Suppose two newborn babies were accidentally mixed up in a hospital, something that rarely happens. In an effort to determine the parents of each baby, the blood types of the parents and the babies were determined.
Baby 1-type B Mrs. Davisson-type B Mrs. Morgan - type O
Baby 2-type O Mr. Davisson- type B Mr. Morgan - type AB
A B
O AO BO
O AO BO
Name
Genotype
Mrs. D
Mr. D
Mrs. M
Mr. M
Baby 1
Baby 2 BO OO AB
BB, BO OO AB
Which baby belongs to Mr. & Mrs. Davisson?
2. Which baby belongs to Mr. and Mrs. Morgan?
Baby 2
Baby 1

55. blood type is located on chromosome #9 Type A, B, AB or O
Chapter 9
blood type is located on chromosome #9
Type A, B, AB or O
RH factor is a separate gene that codes for another protein. This is the positive or negative part of the blood type, on chromosome #1.

56. Many Genes Have Multiple Alleles
A population might have more than two alleles for a given gene.
In Labrador retriever, coat color is determined by one gene with four different alleles. Five different colors result from the combinations of these alleles.  (More on labradors later)
Eye color is also controlled by multiple alleles

57. The simulation is a bit simplified, but the idea is that MULTIPLE ALLELES control a single trait (eye color)
It is likely that more than 2 alleles control eye color, this is simplified just made it simple to understand.

58. Polygenic Traits
Individual heritable characters found to be controlled by groups of several genes, called polygenes.
Each allele intensifies or diminishes the phenotype.
Variation is continuous or quantitative (adding up) - also called quantitative inheritance
Seed Color in wheat - aabbcc, Aabbcc, AaBbcc, AaBbCc, AABbCc, AABBCC (light, intermediate colors, dark)
In humans - hair color, height, skin color

59. Polygenic Inheritance
Pg 197
Polygenic Inheritance
AABBCC x aabbcc (P)
AaBbCc x AaBbCc (F1)
Seven Possible Phenotypes in the F2
The more “dominant” alleles for dark pigmentation (caused by melanin), the darker the skin

60. Figure 11.16

61. Environment and Phenotype
Temperature, water, food sources can have an affect on how a gene is expressed = “multifactoral”
Rabbits have a gene that codes for darker pigments - this gene is more active at low temperatures. Parts of the body that are colder will develop the darker pigmentation - ears and feet 

62. SIAMESE CATS

63. LEGHORN CHICKEN – SINGLE COMB
Multiple Alleles control the combs of chickens.
Assignment:
Multiple Alleles in Chickens
LEGHORN CHICKEN – SINGLE COMB

64. BUTTERCUP CHICKEN - BUTTERCUP COMB

65. Buckeye Chicken – Pea Comb

66. Wyandotte Chicken - Rose Comb

67. Manx cat Lethal Genes (Not in book, added)
Some genes are lethal when both alleles are present. Lethality can occur before or after birth
Huntington's disease in humans is caused by a lethal allele, death occurs later in life
Other examples: Mouse coat color (yellow), Creeper legs in chickens, Manx Cats (no tails)
An example is the "creeper" allele in chickens, which causes the legs to be short and stunted.
Manx cat 

68. X- linked traits

69. Complex Inheritance and Human Heredity
X-linked traits: traits on the X chromosome
Colorblindness
Hemophilia
Muscular Dystrophy
More common in males

70. Colorblindness
sex-linked recessive condition in which people can’t see certain colors
don’t make some of the pigments in the eye that are necessary for color vision.
The most common form is red-green colorblindness

71. Normal color vision : 29
Red green color blind : a bunch of spots!

72. Normal color vision : 56
Red green color blind : 56

73. Normal color vision : 8
Red green color blind : spots

74. Hemophilia: condition that impairs the blood’s ability to clot
Hemophilia: condition that impairs the blood’s ability to clot. Hemophilia is a recessive sex-linked trait.
Also known as bleeders disease

75. Hemophilia: Royal Disease

76. Muscular Dystrophy (MD): disease that results in progressive wasting away of skeletal muscle. Caused by a defective protein known as dystrophin

77. Cross carrier female with normal male
Ex:
Colorblindness
Key: XX = female normal vision
XXe = female carrier (normal vision)
XeXe = female colorblind
XY = male normal vision
XeY = male colorblind
Cross carrier female with normal male
P = XY x X Xe
X Y
Genotype Phenotype
1/4XX: female normal vision
1/4 XXe : female carrier
1/4 XY: male normal vision
¼ XeY: male color blind X Xe
XX XY
XXe XeY
What % of their boys will be expected to be colorblind?
50%

78. Key: XX = normal female Key: XX = normal female MD
Hemophilia
Key: XX = normal female
XXh = female carrier
XhXh = female hemophiliac
XY = male normal
XhY = male hemphiliac MD
Key: XX = normal female
XXm = female carrier
XmXm = female with MD
XY = male normal
XmY = male with MD

79. 7. XeY male colorblind 1. XY male normal 2, XXe female carrier
9. XX or XXe
10. XeY male colorblind
11. XY male normal
12. XeXe female colorblind

80. Complex Inheritance and Human Heredity
Pedigrees:
A diagram that traces the inheritance of a particular trait through several generations

81. Human Disorders

82. Autosomal Recessive vs Autosomal Dominance
Pg 192
Autosomal Recessive vs Autosomal Dominance Aa Aa Aa Aa aa aa

83. Figure 11.10

84. Figure 11.11

85. Hereditary Genetic Disorders
Name of Disorder
Type (autosomal, sex linked, dominant, recessive)
Description/ Symptoms
Type of people group/ treatment / other
Tay Sacks
Cystic Fibrosis
PKU
Sickle Cell Disease
Neurofibromatosis
Huntington's Disease

86. Tay Sachs Autosomal recessive
-progressive deterioration of nerve cells and of mental and physical abilities
Young children begin showing signs of slowed development Severe impairment and death
strikes 1 in 3600 births
100 times greater than incidence among non-Jews
non-functional enzyme fails to breakdown lipids in brain cells
fats collect in cells destroying their function
symptoms begin few months after birth
seizures, blindness & degeneration of muscle & mental performance
child usually dies before 5yo

87. Cystic Fibrosis autosomal recessive -More common in Caucasians
-Mucus in respiratory tract, difficulty breathing
extreme salty sweat
-Mucus may cause secondary infections

88. Effect on Lungs Chloride channel
transports salt through protein channel out of cell
Osmosis: H2O follows Cl–
Effect on Lungs
normal lungs
airway
Cl–
Cl– channel
H2O
cells lining lungs
cystic fibrosis
Cl–
H2O
bacteria & mucus build up
thickened mucus hard to secrete
mucus secreting glands

89. autosomal recessive Phenylketonuria (PKU)
Lack enzyme for normal metabolism
Phenylalanine builds up and causes brain damage
Newborns are routinely tested
Changes in diet lead to normal life
Phenylalanine Hydroxylase is the enzyme needed, absent in those with PKU
autosomal recessive

90. Sickle Cell Disease More common in Africans (African-Americans)
Causes blood to be sickle shaped
Affects oxygen flow to organs, causing weakness, pain, anemia, etc
Heterozygotes are resistant to malaria
AA = normal
Aa = sickle cell trait
aa = sickle cell disease

91. -carry high risk of tumor formation
Neurofibromatosis
-Autosomal dominate
-carry high risk of tumor formation
-Tumors form under skin and can cause skeletal deformities, blindness
"The Elephant Man"
Several years ago, research teams located the exact position of the NF1 gene on chromosome 17. The product of the NF1 gene is a large and complex protein called neurofibromin, which is primarily active in nervous cells as a regulator of cell division. Intensive efforts have let to the identification of the NF2 gene on chromosome 22. The NF2 gene product is a tumor-suppressor protein called merlin.

92. Huntington's Disease
HH = Huntington's
Hh = Huntingtons
hh = normal
Symptoms appear later in life, often starting with poor muscle control
Autosomal Dominant
neurodegenerative genetic disorder that affects muscle coordination and leads to cognitive decline

93. Two dwarfs can have a normal child. Dd x Dd
There are different types of dwarfism. Achondroplasia is caused by a dominant allele.
Meet Kenadie
Two dwarfs can have a normal child. Dd x Dd
Primordial Dwarfism