Genetic
Fundamentals &
Gregor Mendel
Dr. Rick Woodward
Chapters 9 & 10
(New/Green Text Book)
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January 12, 2011
Wednesday
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Today’s Agenda:
-Journal Questions: Why do you think the study of
genetics is important?
What is your New Year’s resolution/goal?
-Turn in your gene mutation winter break project.
*1. Lecture: Genetics & Mendel’s Laws
–Slide 36
2. Genetic Traits Activity: How alike are we?
3. Work on page 43 in packet: Heredity
4. Video: “Ghost in your genes”
5. Homework: Read Chapter 9 “Mendel
Genetics”
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(page 164 - 183: Second page of packet)
The Genesis of Genetics
A. Genetics was founded with
the work of Gregor Johann
Mendel, an Austrian monk
who experimented with
garden peas.
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Mendel’s Experimental Garden
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Situating Mendel Historically
Mendel born
1800
(1831-1836)
(1859)
Darwin on
Darwin’s
Beagle
On the Origin
Voyage
of Species
1815 1830
Napoleon
defeated at
Waterloo
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1845
(1866)
(1892)
(1910)
Mendel’s Weismann’s Morgan
Paper
germ plasm finds white
published
theory
fruit fly
1860 1875 1890
Crimean
War
(1853-1856)
Formation
of German
Empire (1870)
1905
1920
Mendel’s Sex
work re- chromodiscovered somes
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Genetic Terminology
Key Concept!
A. Heredity is the transmission of
characteristics from parents to
offspring.
B. A trait is a specific
characteristic such as height
or eye color.
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Genetics Terminology
C. Molecular genetics is the
study of the structure and
function of chromosomes
and genes.
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Mendel’s
Observations
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A. Mendel observed seven
characteristics in pea
plants.
B. He looked at contrasting
traits:
1. Plant height
(long or short stems)
2. Seed color
(yellow or green)
3. Flower color
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(purple or white)
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Mendel’s Observations
C. Mendel studied each
characteristic and its
contrasting trait individually.
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Mendel’s Experiments: Crossed Pea
Varieties with 7 Clearly Distinguishable Traits
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Mendel’s Observations
D. He began by growing plants
that were pure for each trait.
(1) Plants that are pure for a
trait always produce
offspring for that specific
“pure” trait.
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Mendel’s
Observations
E. The term strain denotes
plants that are pure for
a specific trait.
F. The first strain is
referred to as a parental
generation, or P1
generation.
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Mendel’s Observations
G. When the plants
matured, he recorded the
number of each type of
offspring produced by the
P1 plant.
(1) He called the offspring
of the P1 generation the
first filial generation, or
F1 generation.
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F1 x F1 Punnett square
F2 genotypes
1/4 SS
1/2 Ss
1/4 ss
F2 phenotypes
3/4 smooth
1/4 wrinkled
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Terminology
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A. An allele is an alternative
form of a gene.
(1) Letters are used to
represent alleles. (i.e. T, t)
(2) Dominant Trait: TT
(Tallness)
(3) Recessive Trait: tt
(shortness)
B. Gene: a segment of DNA that
contains coding for a
polypeptide or protein; a unit
of heredity information.
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Terminology
C. Punnett Square: Used for predicting
the probability that certain traits will
be inherited by offspring.
(1) Punnett Square = P for Probability
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Terminology
D. Homozygous: When both
alleles of a pair are alike, or the
same, the organism is said to be
homozygous for that characteristic.
AA = RED
aa = BLUE
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Terminology
E. Heterozygous: When the two
alleles in the pair are different,
the organism is heterozygous
for that characteristic. Tt
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Terminology
F. The genetic makeup of an
organism is its genotype
(1) Combination of alleles
(Rr, rr, RR)
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Genotypic Ratio
1. Cross (Tt) (Tt) using a Punnett square.
2. What is the genotypic ratio?
Genotypic Ratio = 1TT:2Tt:1tt
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Terminology
G. Phenotype is the physical
appearance or expression
of the genotype. (Flower
Color)
(1) Flower Color is the
physical
appearance/phenotype.
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Phenotypic Ratio
1. What is the phenotypic ratio
of a cross between (Tt)(Tt)?
Use a Punnett Square to assist
you.
2. The phenotypic ratio is
3 Tall: 1 Short
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Ratios
F1 x F1 crosses:
Mendel also discovered
that traits that
disappear in the F1
generation reappear in
the F2 generation in a
1:3 ratio.
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Hybrids
A. A hybrid is…..
B. A monohybrid cross is a
cross between individuals
that involves one pair of
contrasting traits (TT)(tt)
C. A Dihybrid cross is a cross
between individuals that
involve two pairs of
contrasting traits.
(BBSS) (ssbb)
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Dihybrid cross:
F1 generation
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Dihybrid cross:
F2 generation
Ratio:
9:3:3:1
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Hybrid Cross
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Dominant versus
Recessive Traits
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Recessive Traits
versus Dominant Traits
A. Recessive Trait: Referring
to an allele that is masked
by the presence of another
allele for the same
characteristic.
(1) Example:
T = Tall
t = Short
tt = Short (recessive trait)
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Recessive Traits
versus Dominant Traits
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Recessive Traits versus
Dominant Traits
B. Dominant Trait: The dominant
trait dominants over a
recessive trait unless the
recessive trait is homozygous
tt = shortness.
(1) Example:
T = Tall
t = Short
TT = Tall (Dominant Trait)
Tt = Tall (Dominant Trait)
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Epigenetics
A. May control the expression of
our genes.
B. Involves the modifications of
the activation of certain genes,
but not the basic structure of DNA
C. Possible Epignetic Processes:
1. Gene silencing
2. Chromosome inactivation
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Today’s Activity:
HOW ALIKE ARE OUR ALLELES?

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Find out the alleles you have for different traits
 For each trait, write down whether you express
that trait and whether you are dominant or
recessive.
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1. TONGUE ROLLING
DOMINANT Trait:
The ability to roll up the sides
of the tongue (RR, Rr)
RECESSIVE Trait:
Not being able to roll up the sides
of the tongue (rr)
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2. 2nd TOE LENGTH

DOMINANT Trait:
2nd toe is longer than the big toe
(BB, Bb)
RECESSIVE Trait:
2nd toe is shorter than the big toe
(bb)
-note the presence of a toe ring.

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3. WIDOW’S PEAK


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DOMINANT Trait:
Hairline has a point, widow’s peak is present
(WW, Ww)
RECESSIVE Trait:
Hairline has no point, no widow’s peak
(ww)
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4. ATTACHED/FREE EARLOBES
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
DOMINANT Trait:
Earlobes hang freely from the ear
(EE, Ee)

RECESSIVE Trait:
Earlobes are attached to the
side of the face
(ee)
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5. HITCHHIKER’S THUMB
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
DOMINANT Trait:
Thumb is straight slightly angled
(HH, Hh)

RECESSIVE Trait:
Thumb can be bent backwards
(hh)
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6. HAIRY KNUCKLES
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
DOMINANT Trait:
No hair on middle parts of fingers
(HH, Hh)

RECESSIVE Trait:
Hair is present on middle parts of
fingers
(hh)
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7. DIMPLES
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
DOMINANT Trait:
Dimples present
(DD, Dd)

RECESSIVE Trait: No dimples
(dd)
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8. CLEFT CHIN
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
DOMINANT Trait:
No cleft present in the chin
(CC, Cc)

RECESSIVE Trait:
Chin has a cleft or indentation
(cc)
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9. STRAIGHT/BENT PINKIES
DOMINANT Trait:
Pinkies are straight
(SS, Ss)
RECESSIVE Trait:
Pinkies are bent
(ss)
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10. HANDEDNESS
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
DOMINANT Trait:
Right-handed
(HH, Hh)

RECESSIVE Trait:
Left-handed
(hh)
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Handedness & The Brain
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January 13, 2011: Thursday
Today’s Agenda:
-Journal Question: What is the difference
between a genotype and a phenotype?
-What is epigenetics?
*(1) Lecture on Mendel’s Laws (finishing unit)
–slide 85
(2) Start Face Lab (last pages of your packet.)
(3) HW: Finish pages 44, 46, 48 in your
packet.
(4) Study guide given out next class.
-Bring flash cards if you need them.
(5) Exam next week on Mendel & Genetics
-All work is due on the day of the exam

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Mendel’s Laws & Other
Key Concepts
1. Mendel’s Law of Segregation
2. Mendel’s Law of Independent
Assortment
3. Mendel’s Law of Dominance
4. Mendel’s Law of Incomplete
Dominance
Other Key Concepts:
1. Blood Types
2. Homologous Chromosomes
3. Crossing Over
4. Sex-Linked Traits (pedigree chart)
5. DNA versus RNA
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Mendel’s Law of Segregation
A. Law of Segregation states
that a pair of factors (alleles)
is segregated, or separated,
during the formation of
gametes (reproductive cells)
(1) When two gametes
combine during fertilization,
the offspring have two
factors controlling a specific
trait (Gg)
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Law of Segregation and Recombination
A. Each trait is transmitted as
an unchanging unit,
independent of other traits,
thereby giving the recessive
traits a chance to recombine
and show their presence in
some of the offspring.
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Mendel’s Law of
Independent Assortment
1. Traits are not inherited
together.
2. In forming the gametes, the
“Factors” for any two traits assort
independently from one another
3. This became known as Mendel’s
second principle: Independent
Assortment
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Independent Assortment
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Mendel’s Law of Dominance
C. Law of Dominance
1. Of two contrasting
characteristics, the
dominant one may
completely mask the
appearance of the
recessive one.
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Mendel’s Law of
Incomplete Dominance
D. Incomplete Dominance
1. Pattern of inheritance in which neither
allele is dominant
2. Three totally different phenotypes
can occur.
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Incomplete Dominance
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Mendel’s Law of Co-dominance
E. Incomplete dominance is
also called Co-dominance
1. Co-dominance occurs
when one allele is not
dominant.
2. Both alleles are
expressed equally.
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Co-Dominance: Blood Types
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What are Blood Types?
Everybody has a blood type. The most common
blood type classification system is the ABO (say "AB-O") system discovered by Karl Landsteiner in the
early 1900s. There are four types of blood in the ABO
system: A, B, AB, and O. Your blood type is
established before you are born, by specific genes
inherited from your parents. You receive one gene
from your mother and one from your father; these
two combine to establish your blood type. These two
genes determine your blood type by causing
proteins called agglutinogens (a-GLOO-tin-a-gins) to
exist on the surface of all of your red blood cells.
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Blood Types
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Blood Types
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What is the most
common blood type?
Answer: Type O Positive
Everyone can accept type O blood.
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Blood Types
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Blood Types
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Homologous
Chromosomes
A. Two copies of each
autosome are called
homologous chromosomes.
(1) They are the same size,
shape, and carry genes for
the same traits.
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Homologous
Chromosomes
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Homologous
Chromosomes
B. Homologous pairs of chromosomes
segregate during meiosis.
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Crossing Over
A. Portions of chromatids may
break off and attach to adjacent
chromatids on the homologous
chromosome = a process called
crossing over.
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Sex-Linked Traits
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A. Sex-linkage is the presence of a
gene on a sex-chromosome.
B. Sex Chromosomes:
XX = Female
XY = Male
C. X-Linked Traits:
(1) Colorblindness
(2) Hemophilia
(3) Duchenne Muscular Dystrophy 71
Sex-Linked Traits
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Pedigree
A. A pedigree is a family record that
shows how a trait is inherited over
several generations.
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Review: DNA vs. RNA
DNA
1. Location: Nucleus
2. Function: Directs activities
of the cell
3. Nitrogen Bases: ATCG
4. Structure: Double Helix
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RNA
Ribosome
Protein Synthesis
AUCG
Single Strand
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Genetic Testing Kits for the Public
A. Genetic Testing kits are
available to check your DNA
for possible anomalies.
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Parts of a Nucleotide
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Nitrogen – Base Pairing
A bonds with T:
C bonds with G
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AT
CG
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Karyotype
A picture of an Individual’s Chromosomes
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Polyploidy
A. When organisms contain some
multiple of the normal number
of chromosomes, they are called
polyploid organisms.
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y
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Recombinant DNA Technology
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Face Lab (January 18, 2011)
- Journal Question: What genetic traits
do you think that you get from your
parents? (Name/Identify 2 traits)
1. Find a friend to perform today’s lab
with.
2. Lab: Data Table & Diagram Your
Results.
(Last pages of your packet)
-Diagram your offspring as a
teenager.
(use color pencils)
3. Write a brief biography of your teen.
4. Homework: Finish your packet & Face
Lab Portrait
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Today’s Lab
Find a partner to work with and perform
the face lab on human genetics.
Materials:
1. Coin
(Heads = Dominant. Tails = Recessive)
2. Lab
3. Color Pencils and paper to diagram
face.
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Today’s Lab
1. Each of you must diagram a
portrait of your child as a
teenager.
2. Name your child
3. On the back of your portrait write
a brief life history of your child.
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Today’s Agenda
January 20, 2011
Journal Questions:
-How do the nitrogen bases pair up in
DNA?
-What are the three parts of a
nucleotide?
*1. Brief Lecture: DNA Replication
2. Complete Face Lab –Draw your
teen and write a brief biography.
3. Work on Study Guide for Exam VI
4. Exam on Monday (Jan. 24, 2011)
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DNA Replication
A. The process of copying DNA in a
cell is called replication.
(1) During replication, the two
nucleotide chains separate by
unwinding, and each chain
serves as a template for a new
nucleotide chain.
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DNA Replication
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Steps of DNA Replication
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(1) Separation of two nucleotide
chains.
a. Point of separation =
Replication fork
(2) Chains are separated by
enzymes called helicases.
(3) Helicase enzymes move
along the DNA molecule, they
break the hydrogen bonds
between the complementary
bases, and the chains
separate.
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Steps of DNA Replication
(4) DNA Polymerases bind to
the separated chains of DNA.
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Steps of DNA Replication
(5) As DNA Polymerases move along
the separated chains, new chains
of DNA are assembled using
nucleotides that are
complementary to the existing
DNA chains.
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Steps of DNA
Replication
(6) The complementary nature of the
two chains of DNA is the
foundation for accurate DNA
replication.
-Nitrogen Base Pairing Rules:
A–T
C–G
GATTACA
CTAATGT (Complementary Strand)
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DNA Replication
When DNA replication is
completed,
(1) Two new exact copies of the
original DNA molecule are
produced
(2) The cell is now ready to
undergo cell division (P.M.A.T).
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Next Topics for the End
of the Semester:
January 27, 2011 (Thursday)
1. Gene Mutations
2. DNA Replication
3. Recombinant DNA Technology
4. Protein Synthesis
-Comprehensive final exam with
emphasis on genetics, the cell,
organelles and their functions.
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