04/21/23 1
Genetic Fundamentals & Gregor Mendel
Dr. Rick Woodward
Chapters 9 & 10 (New/Green Text Book)
04/21/23 2
November 27, 2012Tuesday
Today’s Agenda:
-Journal Questions: Why do you think the study of genetics is important?
*1. Lecture: Genetics & Mendel’s Laws
–Slide 65
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”
(page 164 - 183: Second page of packet)
04/21/23 3
The Genesis of GeneticsA. Genetics was founded with
the work of Gregor Johann Mendel, an Austrian monk who experimented with garden peas.
04/21/23 4
Mendel’s Experimental GardenMendel’s Experimental Garden
04/21/23 5
Situating Mendel HistoricallySituating Mendel Historically
(1831-1836) (1859) (1866) (1892) (1910)Darwin on Darwin’s Mendel’s Weismann’s Morgan
Mendel born Beagle On the Origin Paper germ plasm finds white
Voyage of Species published theory fruit fly
1800 1815 1830 1845 1860 1875 1890 1905 1920
Napoleon Crimean Formation Mendel’s Sex defeated at War of German work re- chromo-Waterloo (1853-1856) Empire (1870) discovered somes
Gregor Mendel’s Genetic Experiments with Dogs Starts a War
04/21/23 6
The Outcome…
04/21/23 7
The Resistance
04/21/23 8
But, there is hope… Little Miracle has arrived..
04/21/23 9
Go Little Miracle..
04/21/23 10
The Dogs Fight Back
04/21/23 11
The Cats Fight Back
04/21/23 12
It is on….
04/21/23 13
Weapons Are Used
04/21/23 14
Spies are deployed…
04/21/23 15
Humans Get Involved
04/21/23 16
Roles are Assigned
04/21/23 17
In the end…
04/21/23 18
Beware the Rise of the Mice
04/21/23 19
04/21/23 20
This is how it begins..
04/21/23 21
04/21/23 22
04/21/23 23
Genetic TerminologyKey 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.
04/21/23 24
Genetics TerminologyC. Molecular genetics is the
study of the structure and function of chromosomes and genes.
04/21/23 25
Mendel’s Observations
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
(purple or white)
04/21/23 26
04/21/23 27
Mendel’s Observations
C. Mendel studied each characteristic and its contrasting trait individually.
04/21/23 28
Mendel’s Experiments: Crossed Pea Mendel’s Experiments: Crossed Pea Varieties with 7 Clearly Distinguishable Varieties with 7 Clearly Distinguishable TraitsTraits
04/21/23 29
Mendel’s ObservationsD. 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.
04/21/23 30
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.
04/21/23 31
04/21/23 32
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.
04/21/23 33
F1 x F1 Punnett square
F2 genotypes
1/4 SS1/2 Ss1/4 ss
F2 phenotypes
3/4 smooth1/4 wrinkled
04/21/23 34
Terminology 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.
04/21/23 35
TerminologyC. Punnett Square: Used for predicting
the probability that certain traits will be inherited by offspring.
(1) Punnett Square = P for Probability
04/21/23 36
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
04/21/23 37
Terminology E. Heterozygous: When the two
alleles in the pair are different, the organism is heterozygous for that characteristic. Tt
04/21/23 38
Terminology
F. The genetic makeup of an organism is its genotype
(1) Combination of alleles (Rr, rr, RR)
04/21/23 39
Genotypic Ratio
1. Cross (Tt) (Tt) using a Punnett square.
2. What is the genotypic ratio?
Genotypic Ratio = 1TT:2Tt:1tt
04/21/23 40
Terminology G. Phenotype is the physical
appearance or expression of the genotype. (Flower Color)
(1) Flower Color is the physical appearance/phenotype.
04/21/23 41
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
04/21/23 42
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.
04/21/23 43
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)
04/21/23 44
Dihybrid cross: F1 generation
04/21/23 45
Dihybrid cross: F2 generation
Ratio:
9:3:3:1
04/21/23 46
Hybrid Cross
04/21/23 47
Dominant versus Recessive Traits
04/21/23 48
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)
04/21/23 49
Recessive Traits versus Dominant Traits
04/21/23 50
Recessive Traits versus Dominant TraitsB. 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)
04/21/23 51
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
04/21/23 52
04/21/23 53
November 27,2012
1. Air pollution may double risk of autism, USC study concludes:
04/21/23 54
Autism: Epigenetics/Environmental Factors:
2. People exposed to poor air quality during pregnancy and in their first year of life are more prone to the effects of autism.
04/21/23 55
04/21/23 56
Today’s Activity:Today’s Activity:HOW ALIKE ARE OUR ALLELES?HOW ALIKE ARE OUR ALLELES?
Find out the alleles you have for different traitsFind out the alleles you have for different traits For each trait, For each trait, write downwrite down whether you express whether you express
that trait and whether you are that trait and whether you are dominant or dominant or recessive.recessive.
04/21/23 57
1. TONGUE ROLLING1. TONGUE ROLLING
DOMINANT Trait: DOMINANT Trait:
The The ability to roll up the sides ability to roll up the sides of the tongue (RR, Rr)of the tongue (RR, Rr)
RECESSIVE Trait:RECESSIVE Trait:
Not being able to roll up the sides Not being able to roll up the sides of the tongue (rr)of the tongue (rr)
04/21/23 58
2. 2nd TOE LENGTH2. 2nd TOE LENGTH
DOMINANT Trait: DOMINANT Trait:
2nd toe is longer than the big toe2nd toe is longer than the big toe
(BB, Bb)(BB, Bb)
RECESSIVE Trait: RECESSIVE Trait:
2nd toe is shorter than the big toe2nd toe is shorter than the big toe
(bb)(bb)
--note the presence of a toe ringnote the presence of a toe ring..
04/21/23 59
3. WIDOW’S PEAK3. WIDOW’S PEAK DOMINANT Trait: DOMINANT Trait:
Hairline has a pointHairline has a point, widow’s peak is present, widow’s peak is present
(WW, Ww)(WW, Ww) RECESSIVE Trait: RECESSIVE Trait:
Hairline has no point, no widow’s peakHairline has no point, no widow’s peak
(ww)(ww)
04/21/23 60
4. ATTACHED/FREE EARLOBES4. ATTACHED/FREE EARLOBES
DOMINANT Trait: DOMINANT Trait:
Earlobes hang freely from the earEarlobes hang freely from the ear
(EE, Ee)(EE, Ee)
RECESSIVE Trait: RECESSIVE Trait:
Earlobes are attached to the Earlobes are attached to the side of the faceside of the face
(ee)(ee)
04/21/23 61
5. HITCHHIKER’S THUMB5. HITCHHIKER’S THUMB
DOMINANT Trait: DOMINANT Trait:
Thumb is straight slightly angledThumb is straight slightly angled
(HH, Hh)(HH, Hh)
RECESSIVE Trait:RECESSIVE Trait:
Thumb can be bent backwardsThumb can be bent backwards
(hh)(hh)
04/21/23 62
6. HAIRY KNUCKLES6. HAIRY KNUCKLES
DOMINANT Trait: DOMINANT Trait:
No hair No hair on middle parts of fingerson middle parts of fingers
(HH, Hh)(HH, Hh)
RECESSIVE Trait: RECESSIVE Trait:
Hair is present on middle parts of Hair is present on middle parts of fingers fingers
(hh)(hh)
04/21/23 63
7. DIMPLES7. DIMPLES
DOMINANT Trait:DOMINANT Trait:
Dimples presentDimples present
(DD, Dd)(DD, Dd)
RECESSIVE Trait: No dimplesRECESSIVE Trait: No dimples
(dd)
04/21/23 64
8. CLEFT CHIN8. CLEFT CHIN
DOMINANT Trait: DOMINANT Trait:
No cleft present in the chinNo cleft present in the chin
(CC, Cc)(CC, Cc)
RECESSIVE Trait: RECESSIVE Trait:
Chin has a cleft or indentationChin has a cleft or indentation
(cc)(cc)
04/21/23 65
9. STRAIGHT/BENT PINKIES9. STRAIGHT/BENT PINKIES
DOMINANT Trait: DOMINANT Trait:
Pinkies are straightPinkies are straight
(SS, Ss)(SS, Ss)
RECESSIVE Trait: RECESSIVE Trait:
Pinkies are bent Pinkies are bent
(ss)(ss)
04/21/23 66
10.10. HANDEDNESSHANDEDNESS
DOMINANT Trait: DOMINANT Trait:
Right-handedRight-handed
(HH, Hh)(HH, Hh)
RECESSIVE Trait: RECESSIVE Trait:
Left-handedLeft-handed
(hh)(hh)
Ghost in Your Genes
1. Write ten facts in your composition book on today’s film.
04/21/23 67
04/21/23 68
Wednesday – Dec 5, 2012 Today’s Agenda:
-Journal Question: What is the difference between a genotype and a phenotype?
-What is epigenetics?
*(1) Lecture on Mendel’s Laws & DNA Replication (finishing unit)
–Slide 110
(2) Start Face Lab (last pages of your packet.)
(3) HW: Work on pages 44, 46, 48 in your packet.
(4) Pick up a Study Guide for the Final Exam
(5) Make up exam on Friday
04/21/23 69
Mendel’s Laws & Other Key Concepts
1. Mendel’s Law of Segregation 2. Mendel’s Law of Independent
Assortment3. Mendel’s Law of Dominance4. Mendel’s Law of Incomplete
DominanceOther Key Concepts:1. Blood Types2. Homologous Chromosomes 3. Crossing Over4. Sex-Linked Traits (pedigree chart)5. DNA versus RNA
04/21/23 70
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)
04/21/23 71
04/21/23 72
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.
04/21/23 73
Mendel’s Law of Mendel’s Law of Independent AssortmentIndependent 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
04/21/23 74
Independent Assortment
04/21/23 75
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.
04/21/23 76
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.
04/21/23 77
Incomplete Dominance
04/21/23 78
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.
04/21/23 79
Co-Dominance: Blood Types
04/21/23 80
What are Blood Types?
Everybody has a blood type. The most common blood type classification system is the ABO (say "A-B-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.
04/21/23 81
Blood Types
04/21/23 82
Blood Types
04/21/23 83
What is the most common blood type?
Answer: Type O Positive
Everyone can accept type O blood.
04/21/23 84
Blood Types
04/21/23 85
Blood Types
04/21/23 86
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.
04/21/23 87
Homologous Chromosomes
04/21/23 88
Homologous Chromosomes
B. Homologous pairs of chromosomes segregate during meiosis.
04/21/23 89
Crossing OverA. Portions of chromatids may
break off and attach to adjacent chromatids on the homologous chromosome = a process called crossing over.
04/21/23 90
Sex-Linked Traits
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
04/21/23 91
Sex-Linked Traits
04/21/23 92
PedigreeA. A pedigree is a family record that
shows how a trait is inherited over several generations.
04/21/23 93
Review: DNA vs. RNA
DNA RNA
1. Location: Nucleus Ribosome
2. Function: Directs activities Protein Synthesis
of the cell
3. Nitrogen Bases: ATCG AUCG
4. Structure: Double Helix Single Strand
04/21/23 94
Genetic Testing Kits for the PublicA. Genetic Testing kits are
available to check your DNA for possible anomalies.
04/21/23 95
Parts of a Nucleotide
04/21/23 96
Nitrogen – Base Pairing
A bonds with T:AT
C bonds with GCG
04/21/23 97
KaryotypeA picture of an Individual’s Chromosomes
04/21/23 98
Polyploidy
A. When organisms contain some multiple of the normal number of chromosomes, they are called polyploid organisms.
04/21/23 99
04/21/23 100
04/21/23 101
y
04/21/23 102
Recombinant DNA Technology
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.
04/21/23 103
DNA Replication
04/21/23 104
Steps of DNA Replication (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.
04/21/23 105
Steps of DNA Replication
(4) DNA Polymerases bind to the separated chains of DNA.
04/21/23 106
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.
04/21/23 107
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)04/21/23 108
DNA ReplicationWhen 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).
04/21/23 109
Putting It All Together The Cell Cycle
04/21/23 110
04/21/23 111
Face Lab- 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
04/21/23 112
Today’s Lab
Find a partner to work with and perform the face lab on human genetics.
Materials:
1. Coin
2. Lab
3. Color Pencils and paper to diagram face.
04/21/23 113
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.
04/21/23 114
Next Topics ….
1. Gene Mutations2. DNA Replication3. Recombinant DNA Technology 4. Protein Synthesis
-Comprehensive final exam with emphasis on genetics, the cell, organelles and their functions.