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The Work of The Work of Gregor Mendel Gregor Mendel 1822-1884 1822-1884

The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

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Page 1: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

The Work ofThe Work ofGregor MendelGregor Mendel

1822-18841822-1884

Page 2: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

Gregor MendelGregor Mendel

1st person to trace successive generations1st person to trace successive generationsof living thingsof living things

Augustinian Monk – BrAugustinian Monk – Bruunn, Austriann, Austriataught natural science in high schooltaught natural science in high school

““How did plants obtain atypical characteristics?”How did plants obtain atypical characteristics?”

Page 3: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

Vocabulary Used in Genetics

phenotype: physical expression of a gene

genotype: a make of genes in a chromosome

homozygous: alleles for a trait are the same

heterozygous: alleles for a trait are opposite TallTall ShortShort

Tall = TTall = T short = tshort = t

T TT T t tt t

T TT T

T tT t

Page 4: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

More Vocabulary Used in GeneticsMore Vocabulary Used in Genetics

traitstraits:: inherited characteristicsinherited characteristics

geneticsgenetics:: study of hereditystudy of heredity

heredity:heredity: passing characteristics from passing characteristics from parents to offspringparents to offspring

Page 5: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

allele:allele: factor that controls expression factor that controls expression of a of a trait trait

filial =filial = son or daughter: son or daughter: FF

parent generation:parent generation: PP

pollinization:pollinization: plant fertilization plant fertilization

zygote:zygote: cell produced by fertilization cell produced by fertilization

fertilization:fertilization: uniting of male and uniting of male and female female gametesgametes

gametes:gametes: sex cells (sperm and egg)sex cells (sperm and egg)

More Vocabulary Used in GeneticsMore Vocabulary Used in Genetics

Page 6: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

Mendel’s FindingsMendel’s Findings:

Hereditary factors do not combine, but are passed Hereditary factors do not combine, but are passed intact to offspring.intact to offspring.

Each member of the parental generation transmitsEach member of the parental generation transmitsonly half of its hereditary factors to each offspring.only half of its hereditary factors to each offspring.

Certain factors are "dominant" over others.Certain factors are "dominant" over others.

Different offspring of the same parents receiveDifferent offspring of the same parents receivedifferent sets of hereditary factors.different sets of hereditary factors.

Mendel's work became, and still is, the foundation Mendel's work became, and still is, the foundation for modern genetics.for modern genetics.

Page 7: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

Mendel's work became, and still is,Mendel's work became, and still is,the foundation for modern genetics.the foundation for modern genetics.

However-------However-------

Mendel's work became, and still is,Mendel's work became, and still is,the foundation for modern genetics.the foundation for modern genetics.

Page 8: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

Gregor Mendel and the Laws of GeneticsGregor Mendel and the Laws of Genetics

I.I. Why Mendel succeeded:Why Mendel succeeded:

A.A. used controlled experimentsused controlled experiments

B.B. studied only one trait at a timestudied only one trait at a time

C.C. did mathematical analysis of did mathematical analysis of datadata

Page 9: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

II.II. Mendel’s Monohybrid CrossesMendel’s Monohybrid Crosses

A.A. First Generation CrossFirst Generation Cross

1. tall pea plants = P1. tall pea plants = P11

2. short pea plants = P2. short pea plants = P11

3. all offspring were tall = F3. all offspring were tall = F11

Page 10: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

B. Second Generation Cross

1. 2 tall offspring from first generation cross = F1

2. ¾ of these offspring = Tall = F2

3. ¼ of these offspring = Short = F2

Page 11: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

C. Mendel’s conclusions: Rules

1. Rule of Unit Factors

Each organism has 2 factors for each of its traits(alleles: gene alternatives)

2. Rule of Dominance

For each trait there exists 2 possible factorsthat are expressed in physical characters,one that may be dominant, and the other recessive.

3. Law of Segregation

The two alleles for each trait must separatewhen gametes form.

Page 12: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

D.D. Expression of TraitsExpression of Traits

1. phenotype: physical expression of a gene

2. genotype: a make of genes on a chromosome

3. homozygous: alleles for a trait are the same

4. heterozygous: alleles for a trait are opposite

Page 13: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

III. Reginald Punnett and the Punnett Squares

A. English Biologist

B. 1905: devised a shorthand way of finding the expected proportions of possible genotypes in the offspring of a cross

C. Method called: Punnett Square

1. Takes into account that fertilizationoccurs randomly

2. Agrees with Mendel’s law of segregation

3. If you know the genotype of the parents,you can use a Punnett square to predictthe possible genotypes of their offspring.

Page 14: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

Punnett SquarePunnett Square

Reginald Punnett 1905Reginald Punnett 1905

Page 15: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

T

T T

t

t

t T t

tTtT

V. Monohybrid Crosses

♂♂

♀♀

Page 16: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

IV.IV. Mendel’s Dihybrid Crosses(cross involving two different traits)

A.A. experimenting with plants that had two different traits that differed from each other

1.1. used true-breeding pea plants that had

round yellow seeds (RRYY) 2.2. crossed with true-breeding pea plants that

had wrinkled green seeds (rryy)

3.3. smooth was dominant and wrinkled was recessive

4.4. yellow was dominant and green was recessive

Page 17: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

yellow seedsRR YY

round seeds

true-breeding pea plants that hadround yellow seeds

RRYY

Page 18: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

green seedsrr yy

wrinkled seeds

rryy

true-breeding pea plants that hadwrinkled green seeds (rryy)

Page 19: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

true-breeding pea plants that had

round yellow seeds

true-breeding pea plants that had

wrinkled green seeds

RRYY (rryy)

++

++

RRYYrryy

RRrrYYrr

or

Page 20: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

r

r

R

RY

y

Y

y

Y Y

y

y

r

r

RR

R

R

R

R

R

R

R

R Y

Y

Y

Y

Y

Y

Y

Y R

R

R

R

R

R

R

R

Y

Y

Y

Y Y

Y

Y

Yr r r r

r r r r

r r r r

r r r r

y y y y

y y yy

y y y y

y y y y

P1P1

Page 21: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

true-breeding pea plants that had

round yellow seeds

true-breeding pea plants that had

wrinkled green seeds

RRYY (rryy)

++

++

Result was 100Result was 100% round yellow seeded plants% round yellow seeded plants

Page 22: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

Offspring of P1 cross pea plants that had

round yellow seeds

Offspring of P1 cross pea plants that had

wrinkled green seeds

RrYy (RrYy)

++

++

Result was different.Result was different.

??

Page 23: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

R

R

R

RY

Y

Y

Y

y y

y

y

r

r

rr

R

R

R

R

R

R

R

R Y

Y

Y

Y

Y

Y

Y

Y r

r

r

r

r

r

r

r

y

y

y

y y

y

y

yR R R R

R R R R

r r r r

r r r r

Y Y Y Y

y y yy

Y Y Y Y

y y y y

F1F1

Page 24: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

9 round yellow

RRYYRrYyRRYyRrYY

3 round green3 round green

RRyy

Rryy

1 wrinkled green1 wrinkled green

rryy

1/164/162/162/16

1/16

2/16

1/16

3 wrinkled yellow3 wrinkled yellow

rrYY

rrYy

1/16

2/16

9/16

3/16

3/16

1/16

16/16

Ratio

= 9:

3:3:

1

Ratio

= 9:

3:3:

1

Page 25: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

B. F1 generation produced all round yellow seeds

C. F2 generation produced

9 round yellow

D. The Law of Independent Assortment

Genes for different traits are inheritedGenes for different traits are inheritedindependently of each other.independently of each other.

3 round green

3 wrinkled yellow

1 wrinkled green

Page 26: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

Haploidn

Page 27: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

Diploid

2n

Page 28: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

S-phase of cell cycleS-phase of cell cycle

2n x 22n x 2

Page 29: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

Meiosis IMeiosis I2n x 22n x 2

2n2n2n2n

AA BB

Page 30: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

Meiosis IIMeiosis II

2n2n

nn

nn

AA

Page 31: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

2n2n

nnnn

BB

Page 32: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

Dominant ExamplesDominant ExamplesBrown Eyes over Blue EyesBrown Eyes over Blue Eyes

Color Vision over Color BlindnessColor Vision over Color Blindness

Hairy Heads over Bald HeadsHairy Heads over Bald Heads

Curly Tongue over Flat TongueCurly Tongue over Flat Tongue

Extra Fingers over Five FingersExtra Fingers over Five Fingers

Double Recessive Examples ExamplesDouble Recessive Examples ExamplesHemophiliaHemophilia

Sickle-Cell DiseaseSickle-Cell DiseaseTay-Sachs DiseaseTay-Sachs Disease

DwarfismDwarfism

Page 33: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

V.V. ProbabilityProbability

Page 34: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

VI. Genetic VariationVI. Genetic Variation

Page 35: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

VII. Crossing OverVII. Crossing Over

Page 36: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

VIII. NONDISJUNCTION

46

23 23

Normal distribution of chromosomes during meiosis.

Page 37: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science
Page 38: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

NONDISJUNCTION

46

24 22

Page 39: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science

Trisomy(21)Trisomy(21) Down SyndromeDown Syndrome

Monosomy:Monosomy: Turner SyndromeTurner Syndrome

Hexapoid:Hexapoid:WheatWheat

Trisomy(13)Trisomy(13) Patau’s SyndromePatau’s Syndrome

Triploid:Triploid: ApplesApples

Polyploid:Polyploid: chrysanthamumschrysanthamums

Page 40: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science
Page 41: The Work of Gregor Mendel 1822-1884 1st person to trace successive generations of living things Augustinian Monk – Brunn, Austria taught natural science