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1 Introductio Introductio n to n to Genetics Genetics All-Star Science
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1 Introduction to Genetics All-Star Science 2 Gregor Mendel (1822-1884) Responsible for the Laws governing Inheritance of Traits Genetics Father of Genetics.

Dec 17, 2015

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Page 1: 1 Introduction to Genetics All-Star Science 2 Gregor Mendel (1822-1884) Responsible for the Laws governing Inheritance of Traits Genetics Father of Genetics.

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IntroductioIntroduction to n to

Genetics GeneticsAll-Star Science

Page 2: 1 Introduction to Genetics All-Star Science 2 Gregor Mendel (1822-1884) Responsible for the Laws governing Inheritance of Traits Genetics Father of Genetics.

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Gregor Gregor MendelMendel

(1822-1884)(1822-1884)Responsible Responsible for the Laws for the Laws governing governing

Inheritance Inheritance of Traitsof Traits

Father of GeneticsGenetics

Page 3: 1 Introduction to Genetics All-Star Science 2 Gregor Mendel (1822-1884) Responsible for the Laws governing Inheritance of Traits Genetics Father of Genetics.

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Gregor Johann MendelGregor Johann MendelAustrian monkAustrian monkStudied the Studied the inheritance of inheritance of traits in pea plantstraits in pea plantsDeveloped the Developed the laws of inheritancelaws of inheritanceMendel's work Mendel's work was not recognized was not recognized until the turn of until the turn of the 20th centurythe 20th century

Page 4: 1 Introduction to Genetics All-Star Science 2 Gregor Mendel (1822-1884) Responsible for the Laws governing Inheritance of Traits Genetics Father of Genetics.

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Gregor Johann MendelGregor Johann MendelBetween 1856 Between 1856 and 1863, Mendel and 1863, Mendel cultivated and cultivated and tested some tested some 28,000 pea plants28,000 pea plantsHe found that He found that the plants' the plants' offspring retained offspring retained traits of the traits of the parentsparentsCalled the Called the “Father of “Father of Genetics"Genetics"

Page 5: 1 Introduction to Genetics All-Star Science 2 Gregor Mendel (1822-1884) Responsible for the Laws governing Inheritance of Traits Genetics Father of Genetics.

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Site of Site of Gregor Gregor Mendel’s Mendel’s experimentexperimental garden al garden in the in the Czech Czech RepublicRepublic

Page 6: 1 Introduction to Genetics All-Star Science 2 Gregor Mendel (1822-1884) Responsible for the Laws governing Inheritance of Traits Genetics Father of Genetics.

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Genetic TerminologyGenetic Terminology

TraitTrait - any characteristic - any characteristic that can be passed from that can be passed from parent to offspring. parent to offspring. HeredityHeredity - passing of - passing of traits from parent to traits from parent to offspring offspring GeneticsGenetics - study of - study of heredity heredity

Page 7: 1 Introduction to Genetics All-Star Science 2 Gregor Mendel (1822-1884) Responsible for the Laws governing Inheritance of Traits Genetics Father of Genetics.

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Types of Genetic Types of Genetic CrossesCrosses

There are different types of There are different types of genetic crosses. We are genetic crosses. We are going to be dealing with going to be dealing with the simplest type.the simplest type.Monohybrid cross Monohybrid cross - - cross cross involving a single traitinvolving a single traite.g. flower color e.g. flower color

Page 8: 1 Introduction to Genetics All-Star Science 2 Gregor Mendel (1822-1884) Responsible for the Laws governing Inheritance of Traits Genetics Father of Genetics.

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Designer Designer “Genes”“Genes”

AllelesAlleles - - two forms of a two forms of a gene gene (dominant & recessive)(dominant & recessive) DominantDominant - - stronger of two genes stronger of two genes expressed in the hybrid; expressed in the hybrid; represented byrepresented by aa capital letter (R)capital letter (R) RecessiveRecessive - - gene that shows up gene that shows up less often in a cross; represented less often in a cross; represented by aby a lowercase letter (r)lowercase letter (r)

Page 9: 1 Introduction to Genetics All-Star Science 2 Gregor Mendel (1822-1884) Responsible for the Laws governing Inheritance of Traits Genetics Father of Genetics.

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More TerminologyMore Terminology

GenotypeGenotype - - gene gene combination for a traitcombination for a trait (e.g. RR, Rr, rr) (e.g. RR, Rr, rr) PhenotypePhenotype - - the physical the physical feature resulting from a feature resulting from a genotypegenotype (e.g. red, white) (e.g. red, white)

Page 10: 1 Introduction to Genetics All-Star Science 2 Gregor Mendel (1822-1884) Responsible for the Laws governing Inheritance of Traits Genetics Father of Genetics.

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Genotype & Phenotype in Genotype & Phenotype in FlowersFlowers

Genotype of alleles:Genotype of alleles:RR = red flower= red flowerrr = yellow flower= yellow flower

All genes occur in pairs, so All genes occur in pairs, so 22 allelesalleles affect a characteristic affect a characteristic

Possible combinations are:Possible combinations are:

GenotypesGenotypes RRRR RRrr rrrr

PhenotypesPhenotypesRED RED RED RED YELLOWYELLOW

Page 11: 1 Introduction to Genetics All-Star Science 2 Gregor Mendel (1822-1884) Responsible for the Laws governing Inheritance of Traits Genetics Father of Genetics.

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GenotypesGenotypesHomozygousHomozygous genotype - gene genotype - gene

combination involving 2 combination involving 2 dominant or 2 recessive genes dominant or 2 recessive genes (e.g. RR or rr);(e.g. RR or rr); also called also called pure pure  HeterozygousHeterozygous genotype - gene genotype - gene combination of one dominant & combination of one dominant & one recessive allele    (one recessive allele    (e.g. Rr);e.g. Rr); also calledalso called hybridhybrid

Page 12: 1 Introduction to Genetics All-Star Science 2 Gregor Mendel (1822-1884) Responsible for the Laws governing Inheritance of Traits Genetics Father of Genetics.

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Punnett SquarePunnett Square

Used to help Used to help solve solve genetics genetics problemsproblems

Page 13: 1 Introduction to Genetics All-Star Science 2 Gregor Mendel (1822-1884) Responsible for the Laws governing Inheritance of Traits Genetics Father of Genetics.

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Genes and Environment Genes and Environment Determine CharacteristicsDetermine Characteristics

Page 14: 1 Introduction to Genetics All-Star Science 2 Gregor Mendel (1822-1884) Responsible for the Laws governing Inheritance of Traits Genetics Father of Genetics.

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Monohybrid Monohybrid CrossesCrosses

Page 15: 1 Introduction to Genetics All-Star Science 2 Gregor Mendel (1822-1884) Responsible for the Laws governing Inheritance of Traits Genetics Father of Genetics.

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Trait: Seed ShapeTrait: Seed Shape

Alleles: Alleles: RR – Round – Round rr – Wrinkled – Wrinkled

Cross: Cross: RoundRound seedsseeds xx Wrinkled Wrinkled seedsseeds

RRRR xx rr rr

Monohybrid CrossMonohybrid Cross

R

R

rr

Rr

RrRr

Rr

Genotype:Genotype: RrRr

PhenotypePhenotype: RoundRound

GenotypicGenotypicRatio:Ratio: All alikeAll alike

PhenotypicPhenotypicRatio:Ratio: All alike All alike

Page 16: 1 Introduction to Genetics All-Star Science 2 Gregor Mendel (1822-1884) Responsible for the Laws governing Inheritance of Traits Genetics Father of Genetics.

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Genetic Practice Genetic Practice ProblemsProblems

Page 17: 1 Introduction to Genetics All-Star Science 2 Gregor Mendel (1822-1884) Responsible for the Laws governing Inheritance of Traits Genetics Father of Genetics.

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Cross these two plants.Cross these two plants.

tall (TT) x dwarf (tt) pea tall (TT) x dwarf (tt) pea plantsplants

T

T

t t

Page 18: 1 Introduction to Genetics All-Star Science 2 Gregor Mendel (1822-1884) Responsible for the Laws governing Inheritance of Traits Genetics Father of Genetics.

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Solution:Solution:

T

T

t t

Tt

Tt

Tt

Tt All Tt = tall(heterozygous tall)

produces theFF11 generation generation

tall (TT) vs. dwarf (tt) pea tall (TT) vs. dwarf (tt) pea plantsplants

Page 19: 1 Introduction to Genetics All-Star Science 2 Gregor Mendel (1822-1884) Responsible for the Laws governing Inheritance of Traits Genetics Father of Genetics.

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Breed the FBreed the F11 generation generation

tall (Tt) vs. tall (Tt) pea plantstall (Tt) vs. tall (Tt) pea plants

T

t

T t

Page 20: 1 Introduction to Genetics All-Star Science 2 Gregor Mendel (1822-1884) Responsible for the Laws governing Inheritance of Traits Genetics Father of Genetics.

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Solution:Solution:

TT

Tt

Tt

tt

T

t

T tproduces theFF22 generation generation

1/4 (25%) = TT1/2 (50%) = Tt1/4 (25%) = tt1:2:1 genotype1:2:1 genotype 3:1 phenotype3:1 phenotype

tall (Tt) x tall (Tt) pea tall (Tt) x tall (Tt) pea plantsplants

Page 21: 1 Introduction to Genetics All-Star Science 2 Gregor Mendel (1822-1884) Responsible for the Laws governing Inheritance of Traits Genetics Father of Genetics.

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