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Pedigrees, Karyotypes, And
Genetics
Tate- Biology
Week of 2-18-2013
Grab Your Journals Folks!!!!
2-18-13
No School- Presidents Day
Staff Work Day/ Student Holiday
2-19-13 Tuesday
Biology
Demonstrate an understanding of
pedigree charts, karyotypes and
genetics ; demonstrate a mastery
of understanding of the cell cycle
and gene control
1.
2.
3.
4.
Review over objective
Notes: Karyotypes and
Pedigrees
Test: Cell Cycle and Gene
Control
Closure: Review Reminders
List
Reminders:
Study DAILY!!!
Keep track of your grade in
skyward on your OWN time.
Formative Assessments are next
week ( science is Thursday)
Extra Credit #2 given out next
week ( will be due on that Friday)
This is the LAST week to retest
the DNA exam if you failed it!
2-19-13
Notes/Study Sheet:
 Academic Term:
 Term in your own
words:
 Illustration /Examples
( you should have these
three things ( minimum)
for your notes.
This is how you will take
notes for Genetics and
Heredity
At the end of each
chapter, notes will be
graded as: homework,
daily, and a quiz grade.
Pedigree
 A pedigree shows the relationships within a family and it
helps to chart how one gene can be passed on from
generation to generation.
 Pedigrees are tools used by genetic researchers or
counselors to identify a genetic condition running
through a family, they aid in making a diagnosis, and aid
in determining who in the family is at risk for genetic
conditions.
On a pedigree:
A circle represents a female
A square represents a male
A horizontal line connecting a male and
female represents a marriage
A vertical line and a bracket connect the
parents to their children
A circle/square that is shaded means the
person HAS the trait.
A circle/square that is not shaded means
the person does not have the trait.
Children are placed from oldest to
youngest.
A key is given to explain what the trait is.
More Terminology to know….
 Genotype - gene combination for a trait (e.g. RR, Rr, rr)
 Phenotype - the physical feature resulting from a
genotype (e.g. red, white)
 Dominant: trait being displayed at all times represented
by a capital letter
 Recessive: trait only displayed when there are no
dominant traits; represented by a lowercase letter
 Homozygous genotype - gene combination involving 2
dominant or 2 recessive genes (e.g. RR or rr); also called
pure
 Heterozygous genotype - gene combination of one
dominant & one recessive allele (e.g. Rr); also called
hybrid
Marriage
Male-DAD
Female-MOM
Has the trait
Male-Son
Female-daughter
Female-daughter
Oldest to youngest
Male- Son
ff
Steps:
•Identify all people who have the
trait.
Ff
•For the purpose of this class all
traits will be given to you. In
other instances, you would have
to determine whether or not the
trait is autosomal dominant,
autosomal recessive, or sexlinked.
•In this example, all those who
have the trait are homozygous
recessive.
•Can you correctly identify all
genotypes of this family?
•F- Normal
•f- cystic fibrosis
Key:
ff
ff
affected male
unaffected male
Ff
Ff
affected female
unaffected female
Pp
Pp
PKU
P- Unaffected
p- phenylketonuria
PP or Pp
Pp
pp
pp
Key:
pp
Pp
affected male
unaffected male
Pp
affected female
unaffected female
hh
 H-huntington’s
disease
 h-Unaffected
Hh
Hh
hh
Hh
hh
Hh
Key:
affected male
unaffected male
hh
hh
affected female
unaffected female
Sex-Linked Inheritance
 Colorblindness
Cy
cc
cy
Cc
Key:
Cc
affected male
unaffected male
cy
cy
affected female
unaffected female
Reading Charts….
Remember….if a circle or square is filled in,
its DOMINANT for the disorder…if its not
shaded in, then its RECESSIVE…and if its
half shaded, shaded lightly or has a line
through it, it’s a carrier for the trait only!!!
How to read a pedigree chart
Extra help:
http://www.youtube.com/watch?v=Ir1t9awm
Ul4
2-20-12 Biology
Reminders:
Biology
Demonstrate an
understanding of
pedigree charts,
karyotypes and genetics
1.Bell Work 39
2. Continue with notes
3. Pedigree Practice
4. Closure: Reminders (
and leave journals)
Study DAILY!!!
Keep track of your grade in skyward
on your OWN time.
Formative Assessments are next
week ( science is Thursday)
Extra Credit #2 given out next week (
will be due on that Friday)
This is the LAST week to retest the
DNA exam if you failed it!
Sex Linked Vs. Autosomal Linked
Chromosomes- a threadlike structure that
contains nucleic acid and proteins that holds
genetic information. ( found in cells)
Autosomes- ANY chromosomes that are
not sex chromosomes. ( 44)
Sex Chromosomes- the chromosomes that
determine an individuals gender or sex. ( 2)
You have 46 chromosomes total: 23 from
dad, 23 from mom.
Karyotypes
To analyze chromosomes, cell biologists
photograph cells in mitosis, when the
chromosomes are fully condensed and
easy to see (usually in metaphase).
The chromosomes are then arranged in
homologous pairs.
Karyotypes
The homologous pairs are then placed in
order of descending size. The sex
chromosomes are placed at the end.
A picture of chromosomes arranged in
this way is known as a karyotype.
Karyotypes
The karyotype is a result of a haploid
sperm (23 chromosomes) fertilizing a
haploid egg (23 chromosomes).
The diploid zygote (fertilized egg)
contains the full 46 chromosomes. (in
humans)
Normal Human Male Karyotype: 46,XY
Normal Human Female Karyotype: 46,XX
Labeling a Karyotype
 To label a karyotype correctly, first list the
number of chromosomes found in the karyotype.
Ex. 46
 Secondly, list the type of sex chromosomes
found in the karyotype. Ex. XX
 Lastly, list the any abnormalities at the
appropriate chromosome number.
Normal Human Female: 46, XX
Normal Human Male: 46, XY
What are abnormalities?
Sometimes, during meiosis, things go
wrong.
The most common error is
nondisjunction, which means “not
coming apart”.
If nondisjunction occurs , abnormal
numbers of chromosomes may find their
way into gametes, and a disorder of
chromosome numbers may result.
Autosomal Chromosome Disorders
Two copies of an autosomal chromosome
fail to separate during meiosis, an
individual may be born with THREE copies
of a chromosome.
This is known as a “Trisomy”
Trisomy 13, Trisomy 18, Trisomy 21.
Down Syndrome
 Most common, Trisomy 21 (down syndrome)
 1 in 800 babies born in U.S. with Trisomy 21.
 Mild to severe mental retardation
 Increased susceptibility to many diseases and a higher frequency of
other birth defects.
Male: 47, XY, +21
Female: 47, XX, +21
Sex Chromosome Disorders
Klinefelter’s
Syndrome,
47
XXY
Turner’s Syndrome (nondisjunction)
Female inherits only one X chromosome
Karyotype: 45, X
Women are sterile, sex organs do not develop
at puberty.
Klinefelter’s syndrome (nondisjunction)
Males receive an extra X chromosome
Karyotype: 47, XXY
The extra X chromosome interferes with
meiosis and prevents ind. from reproducing.
Other Genetic Disorders
Sickle Cell Disease
Characterized by the bent and twisted shape of
the red blood cells.
More rigid and get stuck in capillaries. Blood
stops flowing and can damage cells, tissues,
and organs.
Produced physical weakness and damage to
the brain, heart, and spleen…could be fatal.
Most commonly found in African Americans
(can be linked to the incidence of malaria).
Other Genetic Disorders
Duchenne Musclular Dystrophy
Sex-linked, defective gene for muscle protein.
Progressive weakening and loss of skeletal
muscle.
In U.S., 1 out of every 3000 males born has
condition.
2-21-13 Thursday
Biology
Demonstrate an
understanding of pedigree
charts, karyotypes and
genetics
1. Chapter 11, sec 1 ( 15
min) ( using power-point
notes and the book)
2. Chapter 11, sec 2 –
Genes and ProbabilityPractice
3. Closure
Reminders:
Extra Credit ( given tomorrow,
due next Friday – no exceptions)
Formatives next week !! Oh
Yeah!!!!!!!
Cheer Informational Meeting
today- CHHS @ 6pm JV gym
Mendelelian
Genetics
http://www.youtube.com/watch?v=SGtWssdauME
copyright cmassengale
31
Gregor Mendel
(1822-1884)
Responsible
for the Laws
governing
Inheritance of
Traits
copyright cmassengale
32
Gregor Johann Mendel
Austrian monk
Studied the
inheritance of traits
in pea plants
Developed the laws
of inheritance
Mendel's work was
not recognized until
the turn of the 20th
century
copyright cmassengale
33
Gregor Johann Mendel
Between 1856 and
1863, Mendel
cultivated and tested
some 28,000 pea
plants
He found that the
plants' offspring
retained traits of the
parents
Called the “Father
of Genetics"
copyright cmassengale
34
Site of
Gregor
Mendel’s
experimental
garden in the
Czech
Republic
copyright cmassengale
35
Particulate Inheritance
Mendel stated that
physical traits are
inherited as “particles”
Mendel did not know
that the “particles”
were actually
Chromosomes & DNA
copyright cmassengale
36
Genetic Terminology
 Trait - any characteristic that
can be passed from parent to
offspring
 Heredity - passing of traits from
parent to offspring
 Genetics - study of heredity
copyright cmassengale
37
Types of Genetic Crosses
 Monohybrid cross - cross
involving a single trait
e.g. flower color
 Dihybrid cross - cross involving
two traits
e.g. flower color & plant height
copyright cmassengale
38
Punnett Square
Used to help
solve genetics
problems
copyright cmassengale
39
copyright cmassengale
40
Designer “Genes”
 Alleles - two forms of a gene
(dominant & recessive)
 Dominant - stronger of two genes
expressed in the hybrid; represented
by a capital letter (R)
 Recessive - gene that shows up less
often in a cross; represented by a
lowercase letter (r)
copyright cmassengale
41
More Terminology
 Genotype - gene combination
for a trait (e.g. RR, Rr, rr)
 Phenotype - the physical
feature resulting from a
genotype (e.g. red, white)
copyright cmassengale
42
Genotype & Phenotype in Flowers
Genotype of alleles:
R = red flower
r = yellow flower
All genes occur in pairs, so 2
alleles affect a characteristic
Possible combinations are:
Genotypes
RR
Rr
rr
Phenotypes
RED
RED
YELLOW
copyright cmassengale
43
Genotypes
 Homozygous genotype - gene
combination involving 2 dominant
or 2 recessive genes (e.g. RR or
rr); also called pure
 Heterozygous genotype - gene
combination of one dominant &
one recessive allele (e.g. Rr);
also called hybrid
copyright cmassengale
44
Genes and Environment
Determine Characteristics
copyright cmassengale
45
Mendel’s Pea Plant
Experiments
copyright cmassengale
46
Why peas, Pisum sativum?
Can be grown in a
small area
Produce lots of
offspring
Produce pure
plants when allowed
to self-pollinate
several generations
Can be artificially
cross-pollinated
copyright cmassengale
47
Reproduction in Flowering Plants
Pollen contains sperm
Produced by the
stamen
Ovary contains eggs
Found inside the
flower
Pollen carries sperm to the
eggs for fertilization
Self-fertilization can
occur in the same flower
Cross-fertilization can
occur between flowers
copyright cmassengale
48
Mendel’s Experimental
Methods
Mendel hand-pollinated
flowers using a paintbrush
He could snip the
stamens to prevent selfpollination
Covered each flower
with a cloth bag
He traced traits through
the several generations
copyright cmassengale
49
How Mendel Began
Mendel
produced
pure
strains by
allowing the
plants to
selfpollinate
for several
generations
copyright cmassengale
50
Eight Pea Plant Traits
Seed shape --- Round (R) or Wrinkled (r)
Seed Color ---- Yellow (Y) or Green (y)
Pod Shape --- Smooth (S) or wrinkled (s)
Pod Color --- Green (G) or Yellow (g)
Seed Coat Color ---Gray (G) or White (g)
Flower position---Axial (A) or Terminal (a)
Plant Height --- Tall (T) or Short (t)
Flower color --- Purple (P) or white (p)
copyright cmassengale
51
copyright cmassengale
52
copyright cmassengale
53
Mendel’s Experimental Results
copyright cmassengale
54
Did the observed ratio match the
theoretical ratio?
The theoretical or expected ratio of
plants producing round or wrinkled seeds
is 3 round :1 wrinkled
Mendel’s observed ratio was 2.96:1
The discrepancy is due to statistical
error
The larger the sample the more nearly
the results approximate to the
theoretical ratio
copyright cmassengale
55
Generation “Gap”
Parental P1 Generation = the parental
generation in a breeding experiment.
F1 generation = the first-generation offspring
in a breeding experiment. (1st filial
generation)
From breeding individuals from the P1
generation
F2 generation = the second-generation
offspring in a breeding experiment.
(2nd filial generation)
From breeding individuals from the F1
generation
copyright cmassengale
56
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
copyright cmassengale
57
Monohybrid
Crosses
copyright cmassengale
58
P1 Monohybrid Cross
Trait: Seed Shape
Alleles: R – Round r – Wrinkled
Cross: Round seeds x Wrinkled seeds
RR
x
rr
r
Genotype: Rr
r
Phenotype: Round
R
Rr
Rr
R
Rr
Rr
Genotypic
Ratio: All alike
copyright cmassengale
Phenotypic
Ratio: All alike
59
P1 Monohybrid Cross Review
 Homozygous dominant x
Homozygous recessive
 Offspring all Heterozygous (hybrids)
 Offspring called F1 generation
 Genotypic & Phenotypic ratio is ALL
ALIKE
copyright cmassengale
60
F1 Monohybrid Cross
Trait: Seed Shape
Alleles: R – Round r – Wrinkled
Cross: Round seeds x Round seeds
Rr
x
Rr
R
r
R
RR
Rr
r
Rr
rr
Genotype: RR, Rr, rr
Phenotype: Round &
wrinkled
G.Ratio: 1:2:1
P.Ratio: 3:1
copyright cmassengale
61
F1 Monohybrid Cross Review
 Heterozygous x heterozygous
 Offspring:
25% Homozygous dominant RR
50% Heterozygous Rr
25% Homozygous Recessive rr
 Offspring called F2 generation
 Genotypic ratio is 1:2:1
 Phenotypic Ratio is 3:1
copyright cmassengale
62
What Do the Peas Look Like?
copyright cmassengale
63
…And Now the Test Cross
Mendel then crossed a pure & a
hybrid from his F2 generation
This is known as an F2 or test cross
There are two possible testcrosses:
Homozygous dominant x Hybrid
Homozygous recessive x Hybrid
copyright cmassengale
64
F2 Monohybrid Cross (1st)
Trait: Seed Shape
Alleles: R – Round r – Wrinkled
Cross: Round seeds x Round seeds
RR
x
Rr
R
Genotype: RR, Rr
r
Phenotype: Round
R
RR
Rr
R
RR
Rr
Genotypic
Ratio: 1:1
copyright cmassengale
Phenotypic
Ratio: All alike
65
F2 Monohybrid Cross (2nd)
Trait: Seed Shape
Alleles: R – Round r – Wrinkled
Cross: Wrinkled seeds x Round seeds
rr
x
Rr
R
r
r
Rr
Rr
r
Genotype: Rr, rr
Phenotype: Round &
Wrinkled
rr
G. Ratio: 1:1
rr
P.Ratio: 1:1
copyright cmassengale
66
F2 Monohybrid Cross Review
 Homozygous x heterozygous(hybrid)
 Offspring:
50% Homozygous RR or rr
50% Heterozygous Rr
 Phenotypic Ratio is 1:1
 Called Test Cross because the
offspring have SAME genotype as
parents
copyright cmassengale
67
Practice Your Crosses
Work the P1, F1, and both F2
Crosses for each of the
other Seven Pea Plant
Traits
copyright cmassengale
68
Web Lab
 Click here to
access the Web
Lab - Mendel’s
Peas
 Work with a partner
to complete
Mendel’s
experiments!
2-22-13
Biology
Demonstrate an understanding of
pedigree charts, karyotypes and
genetics
1. Bell Ringer # 40 ( 5 min/ 3 min
review) –
2. Notes: Laws of Inheritance,
Incomplete and CoDominance ( 10-12 min)
3. Who’s your Daddy? ( group
activity) ( 30 min) – Discussion
and Working trough Genetic
Problems- 25 min to work, 5
min to review answers
4. Closure: Reminders ( 3 min)
Reminders:
Extra Credit due next Friday (
daily reminders given in class)check announcements page on
my website.
Formatives Start Monday….are
YOU ready?
Keep track of your grade, the 6
weeks end next Friday, have you
eliminated YOUR zeros?
70
Mendel’s Laws
copyright cmassengale
71
Results of Monohybrid Crosses
Inheritable factors or genes are
responsible for all heritable
characteristics
Phenotype is based on Genotype
Each trait is based on two genes, one
from the mother and the other from
the father
True-breeding individuals are
homozygous ( both alleles) are the
same
copyright cmassengale
72
Law of Dominance
In a cross of parents that are
pure for contrasting traits, only
one form of the trait will appear in
the next generation.
All the offspring will be
heterozygous and express only the
dominant trait.
RR x rr yields all Rr (round seeds)
copyright cmassengale
73
Law of Dominance
copyright cmassengale
74
Law of Segregation
• Each individual has a pair of factors
(alleles) for each trait
• The factors (alleles) segregate (separate)
during gamete (sperm & egg) formation
• Each gamete contains only one factor
(allele) from each pair
• Fertilization gives the offspring two factors
for each trait
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.
copyright cmassengale
76
Applying the Law of Segregation
copyright cmassengale
77
Law of Independent Assortment
Alleles for different traits are
distributed to sex cells (&
offspring) independently of one
another.
This law can be illustrated using
dihybrid crosses.
copyright cmassengale
78
Dihybrid Cross
A breeding experiment that tracks the
inheritance of two traits.
Mendel’s “Law of Independent
Assortment”
a. Each pair of alleles segregates
independently during gamete formation
b. Formula: 2n (n = # of heterozygotes)
copyright cmassengale
79
Question:
How many gametes will be produced
for the following allele arrangements?
Remember: 2n (n = # of heterozygotes)
1. RrYy
2. AaBbCCDd
3. MmNnOoPPQQRrssTtQq
copyright cmassengale
80
Answer:
1. RrYy: 2n = 22 = 4 gametes
RY
Ry
rY ry
2. AaBbCCDd: 2n = 23 = 8 gametes
ABCD ABCd AbCD AbCd
aBCD aBCd abCD abCD
3. MmNnOoPPQQRrssTtQq: 2n = 26 = 64
gametes
copyright cmassengale
81
Dihybrid Cross
Traits: Seed shape & Seed color
Alleles: R round
r wrinkled
Y yellow
y green
RrYy
x
RrYy
RY Ry rY ry
RY Ry rY ry
All possible gamete combinations
copyright cmassengale
82
Dihybrid Cross
RY
Ry
rY
ry
RY
Ry
rY
ry
copyright cmassengale
83
Dihybrid Cross
RY
RY RRYY
Ry RRYy
rY RrYY
ry
RrYy
Ry
rY
ry
RRYy
RrYY
RrYy
RRyy
RrYy
Rryy
RrYy
rrYY
rrYy
Rryy
rrYy
rryy
copyright cmassengale
Round/Yellow:
Round/green:
9
3
wrinkled/Yellow: 3
wrinkled/green:
1
9:3:3:1 phenotypic
ratio
84
Dihybrid Cross
Round/Yellow: 9
Round/green:
3
wrinkled/Yellow: 3
wrinkled/green: 1
9:3:3:1
copyright cmassengale
85
Test Cross
A mating between an individual of unknown
genotype and a homozygous recessive
individual.
Example: bbC__ x bbcc
BB = brown eyes
Bb = brown eyes
bb = blue eyes
CC = curly hair
Cc = curly hair
cc = straight hair
bC
b___
bc
copyright cmassengale
86
Test Cross
Possible results:
bc
bC
b___
C
bbCc
bbCc
or
copyright cmassengale
bc
bC
b___
c
bbCc
bbcc
87
Summary of Mendel’s laws
LAW
DOMINANCE
SEGREGATION
INDEPENDENT
ASSORTMENT
PARENT
CROSS
OFFSPRING
TT x tt
tall x short
100% Tt
tall
Tt x Tt
tall x tall
75% tall
25% short
RrGg x RrGg
round & green
x
round & green
9/16
pods
3/16
pods
3/16
pods
1/16
pods
copyright cmassengale
round seeds & green
round seeds & yellow
wrinkled seeds & green
wrinkled seeds & yellow
88
Incomplete Dominance
and
Codominance
copyright cmassengale
89
Incomplete Dominance
Incomplete dominance, the phenotypes of
the two alleles blend
F1 hybrids have an appearance somewhat
in between the phenotypes of the two
parental varieties.
r
r
Example: snapdragons (flower)
R
red (RR) x white (rr)
RR = red flower
rr = white flower
R
copyright cmassengale
90
Incomplete Dominance
r
r
R Rr
Rr
R Rr
Rr
produces the
F1 generation
All Rr = pink
(heterozygous pink)
copyright cmassengale
91
Incomplete Dominance
copyright cmassengale
92
For example, a cross between a black cat and a
tan cat results in a tabby cat
Codominance
In codominance, an organism that has both alleles of a
gene displays both phenotypes at the same time
Two alleles are expressed (multiple alleles) in
heterozygous individuals.
Example: blood type
1.
2.
3.
4.
type A
type B
type AB
type O
=
=
=
=
IAIA or IAi
IBIB or IBi
I AIB
ii
copyright cmassengale
94
Codominance Problem
Example:homozygous male Type B (IBIB)
x
heterozygous female Type A (IAi)
IA
i
IB
IAIB
IBi
IB
IAIB
IBi
copyright cmassengale
1/2 = IAIB
1/2 = IBi
96
Another Codominance Problem
• Example: male Type O (ii)
x
female type AB (IAIB)
IA
IB
i
IAi
IBi
i
IAi
IBi
copyright cmassengale
1/2 = IAi
1/2 = IBi
97
Codominance
Question:
If a boy has a blood type O and
his sister has blood type AB,
what are the genotypes and
phenotypes of their
parents?
boy - type O (ii) X girl - type AB
(IAIB)
copyright cmassengale
98
Codominance
Answer:
IA
IB
i
i
IAIB
ii
Parents:
genotypes = IAi and IBi
phenotypes = A and B
copyright cmassengale
99
Sex-linked Traits
Traits (genes) located on the sex
chromosomes
Sex chromosomes are X and Y
XX genotype for females
XY genotype for males
Many sex-linked traits carried on X
chromosome
copyright cmassengale
100
Sex-linked Traits
Example: Eye color in fruit flies
Sex Chromosomes
fruit fly
eye color
XX chromosome - female
copyright cmassengale
Xy chromosome - male
101
Sex-linked Trait Problem
Example: Eye color in fruit flies
(red-eyed male) x (white-eyed female)
XRY
x
XrXr
Remember: the Y chromosome in males
does not carry traits.
Xr
Xr
RR = red eyed
Rr = red eyed
R
X
rr = white eyed
XY = male
Y
XX = female
copyright cmassengale
102
Sex-linked Trait Solution:
Xr
XR
XR
Xr
Y
Xr Y
Xr
XR
Xr
Xr Y
50% red eyed
female
50% white eyed
male
copyright cmassengale
103
Female Carriers
copyright cmassengale
104
Genetic Practice
Problems
copyright cmassengale
105
Breed the P1 generation
tall (TT) x dwarf (tt) pea plants
t
t
T
T
copyright cmassengale
106
Solution:
tall (TT) vs. dwarf (tt) pea plants
t
t
T
Tt
Tt
produces the
F1 generation
T
Tt
Tt
All Tt = tall
(heterozygous tall)
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107
Breed the F1 generation
tall (Tt) vs. tall (Tt) pea plants
T
t
T
t
copyright cmassengale
108
Solution:
tall (Tt) x tall (Tt) pea plants
T
t
T
TT
Tt
t
Tt
tt
produces the
F2 generation
1/4 (25%) = TT
1/2 (50%) = Tt
1/4 (25%) = tt
1:2:1 genotype
3:1 phenotype
copyright cmassengale
109