1. Genetics

2. Heredity
Lesson 1

3. Do Now
Video: What are genes?

4. Heredity
The passage of these coded instructions from one generation to the next
Some traits are readily observable – ex: hair color, leaf shape, shape of wing.. Etc.
** others are less obvious ex: defective heart, sickle cell anemia, color blindness

5. Inheritance of chromosomes
Egg + sperm  zygote
egg
meiosis
zygote
mitosis & development
fertilization
sperm

6. Inheritance of genes
On the chromosomes passed from Mom & Dad to offspring are genes
may be same information
may be different information
eye color
(blue or brown?)
eye color
(blue or brown?)

7. Effect of genes Genes come in different versions brown vs. blue eyes
brown vs. blonde hair
alleles

8. Where did the blue eyes go??
Genes affect what you look like X bb BB Bb Bb Bb Bb
Where did the blue eyes go??

9. Why did the blue eyes stay??
Genes affect what you look like… X bb Bb Bb Bb bb bb
Why did the blue eyes stay??

10. Where did the blue eyes come from??
Genes affect what you look like… X Bb Bb
BB or Bb
BB or Bb
BB or Bb bb
Where did the blue eyes come from??

11. What did we show here? Genes come in “versions”
brown vs. blue eye color
alleles
Alleles are inherited separately from each parent
brown & blue eye colors are separate & do not blend
either have brown or blue eyes, not a blend
Some alleles mask others
brown eye color masked blue

12. How does this work? Paired chromosomes have same kind of genes
but may be different alleles
eye color
(blue?)
eye color
(brown?)
hair color

13. In Class Assignment Hereditary Simulation Worksheet
Determining your genes worksheet

14. Homework
History and Terminology worksheet

15. Punnett Crosses
Lesson 2

16. Do Now
Take out Homework from last night & begin looking over the questions for the video
Where do your genes come from?

17. Traits are inherited as separate units
For each trait, an organism inherits 2 copies of a gene, 1 from each parent
a diploid organism inherits 1 set of chromosomes from each parent
diploid = 2 sets of chromosomes
1 from Mom
homologous chromosomes
1 from Dad

18. Making gametes Remember meiosis! B BB BB = brown eyes bb = blues eyes
 brown is dominant over blue
 blue is recessive to brown B b Bb
Remember meiosis!

19. How do we say it? B BB 2 of the same Homozygous BB = brown eyes b
bb = blues eyes bb b
homozygous dominant
homozygous recessive Bb B b
2 different
Heterozygous
Bb = brown eyes

20. Punnett squares B b BB Bb B b Bb bb Bb x Bb X male / sperm
female / eggs Bb bb

21. Genetics vs. appearance
There can be a difference between how an organism looks & its genetics
appearance or trait = phenotype
brown eyes vs. blue eyes
genetic makeup = genotype
BB, Bb, bb
2 people can have the same appearance but have different genetics: BB vs Bb

22. Genetics vs. appearance
How were these brown eyes made?
eye color
(brown)
eye color
(brown)
eye color
(brown)
eye color
(blue)
vs. BB B Bb B b

23. In class assignment
Genetics Practice 1: Basic genetics

24. Homework
Basics Punnett Squares

25. Penny Genetics
Lesson 3
Lab Activity

26. Genetics & The Work of Mendel Lesson 4 26

27. Do Now
BrainPop: heredity

28. Gregor Mendel The Founder of Genetics
An Austrian monk who lived over 100 years ago and studied how traits were passed from 1 generation to the next
He did hundreds of experiments on thousands of pea plants in the monastery and used mathematical analysis to explain who heredity worked

29. Gregor Mendel
Modern genetics began in the mid-1800s in an abbey garden, where a monk named Gregor Mendel documented inheritance in peas
used good experimental design
used mathematical analysis
collected data & counted them
excellent example of scientific method
He studied at the University of Vienna from 1851 to 1853 where he was influenced by a physicist who encouraged experimentation and the application of mathematics to science and a botanist who aroused Mendel’s interest in the causes of variation in plants. After the university, Mendel taught at the Brunn Modern School and lived in the local monastery.
The monks at this monastery had a long tradition of interest in the breeding of plants, including peas. Around 1857, Mendel began breeding garden peas to study inheritance. 29

30. Mendel’s work Bred pea plants ? cross-pollinate true breeding parents
Pollen transferred from white flower to stigma of purple flower
Bred pea plants
cross-pollinate true breeding parents
raised seed & then observed traits
allowed offspring to self-pollinate & observed next generation
all purple flowers result
P = parents
F = filial generation
self-pollinate ? 30

31. Mendel collected data for 7 pea traits31

32. Looking closer at Mendel’s work
true-breeding
purple-flower peas
true-breeding
white-flower peas X
Parents
100%
1st
generation
(hybrids)
purple-flower peas
In a typical breeding experiment, Mendel would cross-pollinate (hybridize) two contrasting, true-breeding pea varieties.
The true-breeding parents are the P generation and their hybrid offspring are the F1 generation.
Mendel would then allow the F1 hybrids to self-pollinate to produce an F2 generation.
self-pollinate
2nd
generation
3:1
75%
purple-flower peas
25%
white-flower peas 32

33. What did Mendel’s findings mean?
Some traits mask others
purple & white flower colors are separate traits that do not blend
purple x white ≠ light purple
purple masked white
dominant allele
functional protein
affects characteristic
masks other alleles
recessive allele
no noticeable effect
allele makes a non-functioning protein
I’ll speak for both of us!
allele producing functional protein
mutant allele malfunctioning protein
homologous chromosomes 33

34. Genotype vs. phenotype
Difference between how an organism “looks” & its genetics
phenotype
description of an organism’s trait
genotype
description of an organism’s genetic makeup F1 P X
purple
white
all purple
Explain Mendel’s results using
…dominant & recessive
…phenotype & genotype 34

35. PP pp Pp Making crosses x Can represent alleles as letters
flower color alleles  P or p
true-breeding purple-flower peas  PP
true-breeding white-flower peas  pp F1 P X
purple
white
all purple PP x pp Pp 35

36. phenotype & genotype can have different ratios
Punnett squares
Aaaaah,
phenotype & genotype can have different ratios
Pp x Pp
1st
generation
(hybrids) %
genotype %
phenotype P p
male / sperm PP
25%
75% Pp
50% P p
female / eggs PP Pp Pp Pp pp
25%
25% pp
1:2:1
3:1 36

37. Law of Segregation
Two alleles in an individual will separate during gamete formation and act independently.

38. Law of Independent Assortment
Describes the relation between different genes.
Ex. Plant Height and Color, if on different chromosomes can act independently during test crosses

39. Law of Independent Assortment

40. Linkage Alleles fail to assort independently because they are on the
same chromosome
Recombination affects
Linkage - The further apart the
genes the more recombination

41. Linked Genes On the same chromosome = inherited together
ex: red hair/freckles (crossing over can “unlink” genes)
Karyotype = photograph of chromosomes with camera attached to a microscope
 paired up and # from largest to smallest
Human karyotype = 22 pairs of perfectly matched chromosomes (autosomes) 1 pair of sex chromosomes XY (male) or XX (female)

42. Egg cells always have 22 autosomes + X
Sperm cells always have 22 autosomes + X or Y
 sperm cells determines the sex of the organism
Probability of having a boy
or girl in pregnancy:
50% chance boy
50% chance girl

43. Inheritance Patterns
Pedigrees – family tree depicting inheritance of a particular trait over several generations
Males are indicated by squares, females by circles
Individuals affected by trait are shaded while those unaffected are unshaded
Carriers of the trait are half shaded

44. Pedigree

45. In class assignment
Simple Genetics Practice Problems

46. Homework
Complete simple genetics practice for homework

47. Gene Expression
Lesson 5

48. Do Now
Directed Reading Activity: Gene Expression

49. Environment effect on genes
Phenotype is controlled by both environment & genes
Human skin color is influenced by both genetics & environmental conditions
Coat color in arctic fox influenced by heat sensitive alleles
The relative importance of genes & the environment in influencing human characteristics is a very old & hotly contested debate
a single tree has leaves that vary in size, shape & color, depending on exposure to wind & sun
for humans, nutrition influences height, exercise alters build, sun-tanning darkens the skin, and experience improves performance on intelligence tests
even identical twins — genetic equals — accumulate phenotypic differences as a result of their unique experiences
Color of Hydrangea flowers is influenced by soil pH 49

50. In class assignment
Gene Expression

51. Homework
Regents Practice Questions

52. Beyond Mendel’s Laws of Inheritance
Lesson 6 52

53. Do Now
Gregor Mendel Video: Heredity

54. Extending Mendelian genetics
Mendel worked with a simple system
peas are genetically simple
most traits are controlled by single gene
each gene has only 2 version
1 completely dominant (A)
1 recessive (a)
But its usually not that simple! 54

55. Incomplete Dominance
Both alleles contribute to produce a trait unlike either parent
Ex: Japanese Morning Glory
Red flowers White flowers
RR X WW
= RW (pink flowers)
OR co-dominance – 2 dominant alleles expressed at the same time

56. Incomplete dominance Hybrids have “in-between” appearance RR WW RW
RR = red flowers
rr = white flowers
Rr = pink flowers
make 50% less color
RR
WW
RW RR Rr rr 56

57. Incomplete dominance P 1st 100% 1:2:1 2nd X true-breeding red flowers
white flowers
100%
100% pink flowers
1st
generation
(hybrids)
self-pollinate
25%
white
2nd
generation
25%
red
1:2:1
50%
pink 57

58. Incomplete dominance RW x RW RR R W RW RR RW R W RW WW RW WW 25% 25%
genotype %
phenotype RR
25%
25% R W
male / sperm
50%
50% RW RR RW R W
female / eggs RW WW
25%
25% RW WW
1:2:1
1:2:1 58

59. Incomplete Dominance Ex: Cattle color Reddish coat White Coat RR X WW
=RW
(Roan – both colors expressed together)

60. Codominance Equal dominance human ABO blood groups 3 version
A, B, i
A & B alleles are codominant
both A & B alleles are dominant over i allele
the genes code for different sugars on the surface of red blood cells
“name tag” of red blood cell 60

61. Multiple Alleles ** More than 2 alleles for each gene Ex: Blood types:
A = IA
B = IB
O = i
Type Genotype
A IA IA or IA i
B IB IB or IB i
AB IA IB
O ii

62. Genetics of Blood type A A A or A i B BB or B i AB O i i pheno-type
genotype
antigen on RBC
antibodies in blood
donation status A
A A or A i
type A antigens on surface of RBC
anti-B antibodies __ B
BB or B i
type B antigens on surface of RBC
anti-A antibodies AB
both type A & type B antigens on surface of RBC
no antibodies
universal recipient O
i i
no antigens on surface of RBC
anti-A & anti-B antibodies
universal donor 62

63. One gene: many effects
The genes that we have covered so far affect only one trait
But most genes are affect many traits
1 gene affects more than 1 trait
dwarfism (achondroplasia)
gigantism (acromegaly)
The genes that we have covered so far affect only one phenotypic character, but most genes are pleiotropic 63

64. A trait may be determined by multiple genes
Combination of genes from both parents
 Polygenic Inheritance
ex: height, birth weight, IQ, skin color
Unlike peas, that are either tall or short, human height has a variety of expression
Bell curve of gene
expression

65. Many genes: one trait Polygenic inheritance
additive effects of many genes
humans
skin color
height
weight
eye color
intelligence
behaviors 65

66. Human skin color AaBbCc x AaBbCc can produce a wide range of shades
most children = intermediate skin color
some can be very light & very dark 66

67. In class assignment
Genetics Practice 3: Blood Types Genetics

68. Homework Co-dominance and incomplete dominance OR Genetics Practice 3
Mutliple Alleles

69. Sex-Linked Genetics
Lesson 7

70. Do Now
Review Genetics Practice 3 OR practice co dominance and incomplete dominance

71. Thomas Morgan
Studied genetics by using the fruit fly (small, easily identified traits, breed quickly, large # of offspring)
He found that some genes were carried on the X chromosomes (in humans also)
They are sex-linked traits
 Male only needs 1 of the alleles to have this trait

72. Human Disorders that are Sex-Linked
Hemophilia – (Queen Victoria line) defect in blood clotting so the person bleeds too much
- usually found in males
- must get the factor from X
Muscular Dystrophy – destruction of muscle cells  gradual loss of function
- usually found in males, die young

73. Human Disorders that are Sex-Linked
3. Color Blindness – can’t tell between red/green
- more common in males
Ex: Male (normal vision) Female carrier (has color blind gene)
Passes from mother to son
 Females are the carriers

74. In couples who have any genetic disorders – genetic counselors can make a chart from which they can predict the “odds” of having a child with a disorder

75. Genetics of sex
Women & men are very different, but just a few genes create that difference
In mammals = 2 sex chromosomes
X & Y
2 X chromosomes = female: XX
X & Y chromosome = male: XY X X X Y 75

76. Sex chromosomes 76

77. Sex-linked traits Sex chromosomes have other genes on them, too X X X
especially the X chromosome
hemophilia in humans
blood doesn’t clot
Duchenne muscular dystrophy in humans
loss of muscle control
red-green color blindness
see green & red as shades of grey X X
Duchenne muscular dystrophy affects one in 3,500 males born in the United States.
Affected individuals rarely live past their early 20s.
This disorder is due to the absence of an X-linked gene for a key muscle protein, called dystrophin.
The disease is characterized by a progressive weakening of the muscles and loss of coordination. X Y 77

78. Sex-linked traits XHY HH XHXh Hh x XHY Y XH XH Y XHXH XHXH XHY XHY XH
sex-linked recessive
XHY HH
XHXh Hh
2 normal parents,
but mother is carrier x
XHY Y XH XH Y
male / sperm
XHXH
XHXH
XHY
XHY XH Xh
female / eggs
XHXh XH Xh
XHXh
XHXh
XhY
XhY 78

79. Dominant ≠ most common allele
Because an allele is dominant does not mean…
it is better, or
it is more common
Polydactyly
dominant allele 79

80. Polydactyly recessive allele far more common than dominant
individuals are born with extra fingers or toes
the allele for >5 fingers/toes is DOMINANT & the allele for 5 digits is recessive
recessive allele far more common than dominant
 only 1 individual out of 500
has more than 5 fingers/toes
 so 499 out of 500 people are homozygous recessive (aa) 80

81. In class assignment
genetics_xlinked

82. Homework
X-Linked Worksheet

83. Variations on a Human Face
Variations Lab