Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria...

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Classical Genetics

Transcript of Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria...

Page 1: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

Classical Genetics

Page 2: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

The Work and Conclusions of Gregor Mendel

Father of genetics

Monk in Austria

1865

Studied patterns of inheritance in peas

Page 3: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

Why Peas?

Page 4: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

Why Peas?

Self-fertilization produces true breeding generations

Page 5: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

•Prevented self-fertilization

•Manipulated reproduction

•Began monohybrid crosses

•Carefully examined results

Why Peas?

Read Concept 1

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Page 6: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

Why Peas?

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Page 7: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

Mendel’s Work

Some traits are dominant and some are recessive

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Page 8: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

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. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

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. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

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. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

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. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

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. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

Mendel’s Work

Page 14: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

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 15: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.
Page 16: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

Mendel’s Conclusions

2. Law of Segregation

The two alleles for a trait separate during the formation of gametes

Page 17: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

Test Cross

Page 18: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

Dihybrid Cross

Page 19: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

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 20: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

Incomplete Dominance

Page 21: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

“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 22: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

Co-DominanceTwo or more alleles are fully dominant

When present together they are both expressed

ABO Blood Groups exhibit co-dominace

Page 23: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

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 24: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

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 25: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

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 26: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

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 27: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.
Page 28: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.
Page 29: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.
Page 30: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.
Page 31: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

Sex Inheritance

Sex Chromosomes X or Y

XX is female

XY is male

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Page 32: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

Sex-Linked Inheritance

Genes linked to sex chromosomes

Page 33: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

GENETICGENETIC DISORDERS

Page 34: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

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 35: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

Deletion

• One or more genes are lost from a chromosome during division

• Occurs if homologous chromosomes cross over unequally during meiosis

Page 36: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

Duplication

• Chromosome receives an extra piece, which duplicates some genes

Page 37: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

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 38: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

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 39: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.
Page 40: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

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 41: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

Turner Syndrome• XO

• phenotype-female

• small functioning ovaries

• short

• no breast development

Page 42: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

Down Syndrome• Extra chromosome at the 21st position

• Enlarged tongues

• Small, round ears • Heart defects

• Stubby fingers and toes

• Mental retardation

Page 43: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

Klineflelter Syndrome

• XXY at 23rd position

• small testes, no sperm development

• enlarged breast development

• tall stature

Page 44: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

Cri-du-chat• Partial deletion from

chromosome # 5• Baby’s cry sounds like a

cat• Severe mental

retardation• Multiple anatomical

malformations

Page 45: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

Sex-linked Disorders

Page 46: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

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 47: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

Autosomal Dominate Disorders

Page 48: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

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 49: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

Huntington Disease• Progressive degeneration of brain cortex • Symptoms begin around the age of 30-50• Symptoms include

• depression• forgetfulness• clumsiness• twitching• mood swings

Page 50: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

Autosomal Recessive Disorders

Page 51: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

Porphyria

• Prophyrin build-up(molecules formed during the synthesis of hemoglobin)• “werewolf”• emotionally unstable• sensitive to light• self mutilation

Page 52: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

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 53: Classical Genetics. The Work and Conclusions of Gregor Mendel Father of genetics Monk in Austria 1865 Studied patterns of inheritance in peas.

Leprechanism

• Short, elf-like appearance

• Hypoglycemia

Progeria• Premature aging

• Die of artery disease at age 10-15