classical genetics lecture
TRANSCRIPT
![Page 1: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/1.jpg)
Classical Genetics
![Page 2: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/2.jpg)
The Work and Conclusions of Gregor Mendel
Father of genetics
Monk in Austria
1865
Studied patterns of inheritance in peas
![Page 3: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/3.jpg)
Why Peas?
![Page 4: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/4.jpg)
Why Peas?
Self-fertilization produces true breeding generations
![Page 5: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/5.jpg)
•Prevented self-fertilization
•Manipulated reproduction
•Began monohybrid crosses
•Carefully examined results
Why Peas?
Read Concept 1
Click Animation and View
![Page 7: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/7.jpg)
Mendel’s Work
Some traits are dominant and some are recessive
Read concept 3
Click animation and view
Read concept 4
Click animation and view
![Page 8: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/8.jpg)
Mendel’s Work
1. Traits are passed on by factors (genes)
2. Factors (genes) have more than 1 form called alleles
3. There are at least 2 alleles for each trait
![Page 9: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/9.jpg)
Mendel’s Work
Alleles are represented by the first letter of the dominant trait
Pea plant flower color (trait)
Purple or white
Purple is dominant over white
Alleles are represented as
P=purple p=white
![Page 10: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/10.jpg)
You try a few…
1. Round seeds are dominant over wrinkled seeds
2. Yellow seeds are dominant over green seeds
3. Tall plants are dominant over short plants
1. R=round r=wrinkled
2. Y=yellow y=green
3. T=tall t= short
Mendel’s Work
![Page 11: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/11.jpg)
Mendel’s WorkDescribing Traits (Tall or short plants)
Genotype
The actual genetic make-up of an organism
the “genes”
Phenotype
The physical appearance or form observed
the “physical”
![Page 12: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/12.jpg)
Mendel’s WorkPossible Genotypes (TT Tt tt)
Homozygous
The two alleles for the trait are identical
TT homozygous dominant (purebred dominant)
tt homozygous recessive (purebred recessive)
Heterozygous
The two alleles for the trait are different
Tt heterozygote (hybrid)
![Page 13: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/13.jpg)
Mendel’s Work
![Page 14: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/14.jpg)
Mendel’s Work
Read Concept 5
Click animation and view
Complete visual organizer of Mendel’s pea plant experiment
![Page 15: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/15.jpg)
1. Law of Dominance
Alleles for a trait are either dominant or recessive
The dominant form is expressed and the recessive form is hidden
The only way to express a recessive trait is if there are two copies of the recessive allele
Mendel’s Conclusions
![Page 16: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/16.jpg)
![Page 17: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/17.jpg)
Mendel’s Conclusions
2. Law of Segregation
The two alleles for a trait separate during gametogenesis
![Page 18: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/18.jpg)
Test Cross
![Page 19: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/19.jpg)
Dihybrid Cross
![Page 20: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/20.jpg)
Mendel’s 3rd Law of Independent Assortment
• Alleles of different genes are assorted independently of one another during the formation of gametes
• This means that calculating the probability of several traits appearing together is the product of the probability of each trait taken separately
• The Rule of Multiplication
![Page 21: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/21.jpg)
Incomplete Dominance
![Page 22: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/22.jpg)
“Dominant” gene does not fully express itself to mask the effect of the recessive gene
A pattern of inheritance in which the phenotype of a heterozygous individual is intermediate between those of the parents
Genotypic ratio is equal to phenotypic ratio
![Page 23: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/23.jpg)
Co-DominanceTwo or more alleles are fully dominant
When present together they are both expressed
ABO Blood Groups exhibit co-dominace
![Page 24: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/24.jpg)
Type A Blood
•Individuals with group A blood have red blood
cells with antigen A on their surface. •Produce antibodies against antigen B,
antibody B.
•Therefore, a group A person can only receive
blood from people in groups A or O
![Page 25: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/25.jpg)
Type B Blood• Antigen B is on their cells, and
antibodies A are produced in their serum.
• A group B person can only receive blood from people in groups B or O, preferably B.
![Page 26: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/26.jpg)
Type AB
• Individuals with group AB blood have red blood cells with both antigens A and B.
• Do not produce antibodies A or B against either antigen in their serum.
• A person with type AB blood can receive blood from any group (preferably AB) but cannot donate blood except to another AB (universal recipient).
![Page 27: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/27.jpg)
Type O
• Individuals with group O blood have red blood cells with neither antigen A or B.
• Produce antibodies A and B against both types of antigens.
• A group O person can only receive blood from group O (universal donor).
![Page 28: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/28.jpg)
![Page 29: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/29.jpg)
![Page 30: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/30.jpg)
![Page 31: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/31.jpg)
![Page 32: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/32.jpg)
Sex Inheritance
Sex Chromosomes X or Y
XX is female
XY is male
Read concept 9
Click animation and view
![Page 33: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/33.jpg)
Sex-Linked Inheritance
Genes linked to sex chromosomes
![Page 34: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/34.jpg)
GENETICGENETIC DISORDERS
![Page 35: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/35.jpg)
Sources of Genetic Disorders• Chromosome Mutations
• Change in the genetic material on the chromosome
• Four types of chromosome mutations– Deletion, duplication, translocation and
inversion
• Change in chromosome number• Failure of homologous chromosomes to
separate during meiosis–Non-Disjunction
![Page 36: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/36.jpg)
Deletion
• One or more genes are lost from a chromosome during division
• Occurs if homologous chromosomes cross over unequally during meiosis
![Page 37: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/37.jpg)
Duplication
• Chromosome receives an extra piece, which duplicates some genes
![Page 38: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/38.jpg)
Translocation
• A whole chromosome or piece of chromosome attaches to a chromosome in a different pair
• Results in extra or lost genes
• May break up important gene arrangements and change the phenotype of the organism
![Page 39: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/39.jpg)
Inversion
• Part of chromosome breaks off and reattaches itself in reverse order
• May cause no change because it is not losing genes
• Changes the arrangement and may upset important gene interactions
![Page 40: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/40.jpg)
![Page 41: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/41.jpg)
Nondisjunction
• Failure of chromosome to separate during division– Mitosis
• Cell dies, organism is not harmed
– Meiosis
• Results in an abnormal gamete that will produce abnormal offspring
![Page 42: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/42.jpg)
Turner Syndrome• XO
• phenotype-female
• small functioning ovaries
• short
• no breast development
![Page 43: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/43.jpg)
Down Syndrome• Extra chromosome at the 21st position
• Enlarged tongues
• Small, round ears • Heart defects
• Stubby fingers and toes
• Mental retardation
![Page 44: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/44.jpg)
Klineflelter Syndrome
• XXY at 23rd position
• small testes, no sperm development
• enlarged breast development
• tall stature
![Page 45: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/45.jpg)
Cri-du-chat• Partial deletion from
chromosome # 5• Baby’s cry sounds like a
cat• Severe mental
retardation• Multiple anatomical
malformations
![Page 46: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/46.jpg)
Sex-linked Disorders
![Page 47: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/47.jpg)
Hemophilia
• mental retardation
• enlarged liver
• flat broad nose, large tongue
• inability to clot blood properly
• bruise easily
• many patients have been infected
with AIDS
Hunters Syndrome
![Page 48: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/48.jpg)
Autosomal Dominate Disorders
![Page 49: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/49.jpg)
Neurofibromatosis
• Disorder of connective tissue
• Affects bone, eyes, heart and blood vessels
• Long legs and hands
• Blood vessels lack elasticity
• Can be slight to severe• Tumors on head, neck, and spine
Marfan Syndrome
![Page 50: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/50.jpg)
Huntington Disease• Progressive degeneration of brain cortex • Symptoms begin around the age of 30-50• Symptoms include
• depression• forgetfulness• clumsiness• twitching• mood swings
![Page 51: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/51.jpg)
Autosomal Recessive Disorders
![Page 52: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/52.jpg)
Porphyria
• Prophyrin build-up(molecules formed during the synthesis of hemoglobin)• “werewolf”• emotionally unstable• sensitive to light• self mutilation
![Page 53: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/53.jpg)
Cystic Fibrosis
• very common, 40% of population are carriers
• disease of exocrine glands, build up of thick mucus in the lungs that makes breathing difficult
• causes respiratory infections
![Page 54: Classical Genetics Lecture](https://reader033.vdocuments.net/reader033/viewer/2022061601/555cfe1ed8b42a08668b526e/html5/thumbnails/54.jpg)
Leprechanism
• Short, elf-like appearance
• Hypoglycemia
Progeria• Premature aging
• Die of artery disease at age 10-15