Joke of the Day 1 RATIO A comparison

Joke of the Day: 1

RATIO: A comparison of two numbers 1 : 1 COPYRIGHT CMASSENGALE 2

RATIO: A comparison of two numbers 2 : 1 COPYRIGHT CMASSENGALE 3

RATIO: A comparison of two numbers 2 : 1 : 2 1 COPYRIGHT CMASSENGALE 4

RATIO: A comparison of two numbers 1 : 2 : 1 COPYRIGHT CMASSENGALE 5

RATIO: A comparison of two numbers 1 : 0 COPYRIGHT CMASSENGALE 6

UNIT 8: GENETICS MENDELELIAN GENETICS COPYRIGHT CMASSENGALE 7

Gregor Mendel (1822 -1884) “Father of Genetics“ Responsible for the Laws governing Inheritance of Traits COPYRIGHT CMASSENGALE 8

GREGOR JOHANN MENDEL §Austrian monk §Studied the inheritance of traits in pea plants §Developed the laws of inheritance §Mendel's work was not recognized until the turn of the 20 th century COPYRIGHT CMASSENGALE 9

GREGOR JOHANN MENDEL §Mendel cultivated and tested some 28, 000 pea plants §He found that the plants' offspring retained traits of the parents COPYRIGHT CMASSENGALE 10

PARTICULATE INHERITANCE §Mendel stated that physical traits are inherited as “particles” §Mendel did not know that the “particles” were actually Chromosomes & DNA COPYRIGHT CMASSENGALE 11

SITE OF GREGOR MENDEL’S EXPERIMEN TAL GARDEN IN THE CZECH REPUBLIC COPYRIGHT CMASSENGALE 12

GENETIC TERMINOLOGY §Genetics – Study of Heredity §Heredity - Passing of traits from parent to offspring COPYRIGHT CMASSENGALE 13

DESIGNER “GENES” §Alleles - Different forms of a Gene (dominant & recessive) §Dominant - Stronger of two genes expressed; represented by a capital letter. example: (R) §Recessive – Weaker of two genes; represented by a lowercase letter. example: (r) COPYRIGHT CMASSENGALE 14

MORE TERMINOLOGY §Genotype – “Gene ” genetic makeup – “ of a trait. Examples: (RR, Rr, rr) §Phenotype - the physical characteristics resulting from a genotype Examples: (red, white, tall, short) COPYRIGHT CMASSENGALE 15

GENOTYPES §Homozygous- “Purebred” gene combination involving 2 dominant or 2 recessive alleles example: (RR or rr) §Heterozygous- “Hybrid” gene combination of one dominant & one recessive allele example: (Rr) COPYRIGHT CMASSENGALE 16

GENOTYPE & PHENOTYPE IN FLOWERS Genotype of alleles: R = red flower r = yellow flower All genes occur in pairs, so 2 alleles affect a characteristic Possible combinations are: Genotypes RR Phenotypes Red Rr rr Red Yellow COPYRIGHT CMASSENGALE 17

TYPES OF GENETIC CROSSES §Monohybrid cross - cross involving a single trait example: flower color §Dihybrid cross - cross involving two traits example: flower color & plant height COPYRIGHT CMASSENGALE 18

PUNNETT SQUARE Diagram showing the gene combinations that might result from a genetic cross • Letters on the outside represent the Genotypes of the parents • Letters on the inside represent the Genotype possibilities of the offspring COPYRIGHT CMASSENGALE 19

MONOHYBRID CROSSES COPYRIGHT CMASSENGALE 20

EIGHT PEA PLANT TRAITS Seed shape --- Round (R) or Wrinkled (r) Seed Color ---- Yellow (Y) or Green (y) Pod Shape --- Smooth (S) or wrinkled (s) Pod Color --- Green (G) or Yellow (g) Seed Coat Color --- Gray (G) or White (g) Flower position---Axial (A) or Terminal (a) Plant Height --- Tall (T) or Short (t) Flower color --- Purple (P) or white (p) COPYRIGHT CMASSENGALE 21

MONOHYBRID CROSS Trait: Seed Shape Alleles: R – Round r – Wrinkled Cross: Round seeds x Round seeds Rr R RR Rr rr x Rr Genotype: RR, Rr, rr Phenotype: Phenotype Round & wrinkled Genotypic Ratio: 1: 2: 1 Phenotypic Ratio: 3: 1 22

MONOHYBRID CROSS Trait: Seed Shape Alleles: R – Round r – Wrinkled Cross: Round seeds x Round seeds RR R r R RR Rr x Rr Genotype: RR, Rr Phenotype: Phenotype Round Genotypic Ratio: 1: 1 Phenotypic Ratio: All alike COPYRIGHT CMASSENGALE 23

MONOHYBRID CROSS Trait: Seed Shape Alleles: R – Round r – Wrinkled Cross: Wrinkled seeds x Round seeds rr R r r Rr Rr r rr rr x Rr Genotype: Rr, rr Phenotype: Phenotype Round & Wrinkled G. Ratio: 1: 1 P. Ratio: 1: 1 COPYRIGHT CMASSENGALE 24

MONOHYBRID CROSS Trait: Seed Shape Alleles: R – Round r – Wrinkled Cross: Round seeds x Wrinkled seeds RR x rr Genotype: Rr r r R Rr Rr Genotypic Ratio: All alike R Rr Rr Phenotypic Ratio: All alike Phenotype: Phenotype Round COPYRIGHT CMASSENGALE 25

BLOCK 2 BELL RINGER: BIRD CROSS Trait: Alleles: Feather Color Grey (G) White (g) 1. Cross a heterozygous grey feathered bird with a heterozygous grey bird a. Parent’s alleles b. Do a Punnett square c. Genotype Possibilities? d. Genotype Ratio? e. Phenotype Possibilities? f. Phenotype Ratio? COPYRIGHT CMASSENGALE 26

BELL RINGER: MONOHYBRID CROSS Trait: Feather Color Alleles: G – Grey g – White Cross: Grey Feathers x Grey Feathers Gg x Gg G GG Gg gg Genotype: GG, Gg, gg Phenotype: Phenotype Grey, white Genotypic Ratio: 1: 2: 11 Phenotypic Ratio: 3: 1 COPYRIGHT CMASSENGALE 27

REVIEW Spot check Go over monohybrid cross worksheet COPYRIGHT CMASSENGALE 28

TODAY: BIKINI BOTTOM GENETICS COPYRIGHT CMASSENGALE 29

BELL RINGER: It is on the white board today COPYRIGHT CMASSENGALE 30

BELL RINGER: MONOHYBRID CROSS Trait: Hair Texture Alleles: F – Fine f – Course Cross: Cross a fine haired hybrid mouse with a mouse that is heterozygous for fine hair. Ff x Ff F f FF Ff Ff ff Genotypes: FF, Ff, ff Phenotypes: Phenotypes Fine and Course Genotype Ratio: 1: 2: 1 Phenotype Ratio: 3: 1 31

JOKE OF THE DAY: 32

MENDEL’S LAWS 33

LAW OF DOMINANCE Some alleles are dominant and others are recessive Example: - Brown Hair is dominant over blonde. COPYRIGHT CMASSENGALE 34

LAW OF DOMINANCE COPYRIGHT CMASSENGALE 35

LAW OF SEGREGATION In Gametes (eggs or sperm), two alleles responsible for a trait separate from each other. Alleles are then "recombined" at fertilization, producing the genotype for the traits of the offspring. 36

APPLYING THE LAW OF SEGREGATION COPYRIGHT CMASSENGALE 37

LAW OF INDEPENDENT ASSORTMENT Genes for different traits can segregate independently during the formation of gametes. (Genes don’t influence each other) COPYRIGHT CMASSENGALE 38

Principle of Probability The likelihood that a particular event will occur Can be used to predict the outcomes of genetic crosses.

DIHYBRID CROSS: (2 FACTORS) A punnett square that tracks the inheritance of two traits. COPYRIGHT CMASSENGALE 40

DIHYBRID CROSS Traits: Seed shape & Seed color Alleles: R round r wrinkled Y yellow y green Rr. Yy RY Ry r. Y ry x Rr. Yy RY Ry r. Y ry All possible gamete combinations COPYRIGHT CMASSENGALE 41

DIHYBRID CROSS RY Ry r. Y ry COPYRIGHT CMASSENGALE 42

DIHYBRID CROSS RY RY RRYY Ry RRYy r. Y Rr. YY ry Rr. Yy Ry r. Y ry RRYy Rr. YY Rr. Yy RRyy Rr. Yy Rryy Rr. Yy rr. YY rr. Yy Rryy rr. Yy rryy Round/Yellow: 9 Round/green: 3 wrinkled/Yellow: 3 wrinkled/green: 1 9: 3: 3: 1 phenotypic ratio COPYRIGHT CMASSENGALE 43

DIHYBRID CROSS Round/Yellow: 9 Round/green: 3 wrinkled/Yellow: 3 wrinkled/green: 1 9: 3: 3: 1 COPYRIGHT CMASSENGALE 44

BELL RINGER Cross a heterozygous tall, heterozygous red flower with a heterozygous tall, white flower. Parent’s (P 1) genotype Offspring’s (F 1) genotypes Ratio Phenotypes ratio COPYRIGHT CMASSENGALE 45

JOKE OF THE DAY: 46

SPECIAL GENETIC CASES: COPYRIGHT CMASSENGALE 47

INCOMPLETE DOMINANCE DEFINITION: ONE ALLELE IS NOT COMPLETELY DOMINANT OVER ANOTHER (BLEND OR MIX TOGETHER). Red + White = Pink COPYRIGHT CMASSENGALE 48

INCOMPLETE DOMINANCE A case in which one allele is not completely dominant over another allele Example: Flower red (rr) x white (ww) rr = red flower ww = white flower r w w r COPYRIGHT CMASSENGALE 49

INCOMPLETE DOMINANCE Trait: Flower Color Red (r): Incomplete Dominant White (w): Incomplete Dominant Homozygous Red (rr) X Homozygous White (ww) w w rw rw r 100% rw = Pink (Heterozygous Pink) COPYRIGHT CMASSENGALE 50

CODOMINANCE Definition: Both alleles contribute to the phenotype of the organism. Examples: Roan Cattle and Speckled Chickens COPYRIGHT CMASSENGALE 51

CODOMINANCE PROBLEM SPECKLED CHICKEN Example: (BB) (WW) Homozygous male Black x Homozygous female White B W BW BW 100% BW = Speckled (Heterozygous Speckled) COPYRIGHT CMASSENGALE 52

ANOTHER CODOMINANCE PROBLEM • Example: male heterozygous (BW) x female heterozygous (BW) B B W W BB BW BW WW 1/4 = BB 1/2 = BW COPYRIGHT CMASSENGALE 53

SEX-LINKED TRAITS COPYRIGHT CMASSENGALE 54

SEX-LINKED TRAITS Traits (genes) located on the sex chromosomes Sex chromosomes are X and Y XX genotype for females XY genotype for males Many sex-linked traits carried on X chromosome COPYRIGHT CMASSENGALE 55

SEX-LINKED TRAITS Example: Eye color in fruit flies Sex Chromosomes fruit fly eye color XX chromosome - female Xy chromosome - male COPYRIGHT CMASSENGALE 56

SEX-LINKED TRAIT PROBLEM Example: Eye color in fruit flies (red-eyed male) x (white-eyed female) XRY x Xr. Xr Remember: the Y chromosome in males does not carry traits. RR = red eyed r r X X Rr = red eyed rr = white eyed XR XY = male XX = female Y COPYRIGHT CMASSENGALE 57

SEX-LINKED TRAIT SOLUTION: Xr XR XR Xr Y Xr XR Xr Xr Y 50% red eyed female 50% white eyed male COPYRIGHT CMASSENGALE 58

FEMALE CARRIERS COPYRIGHT CMASSENGALE 59

Bell Ringer: Monohybrid Cross (B) Brown Eyes = Dominant (b)Blue Eyes = Recessive Genetic Problem: Cross a male who is homozygous for brown eyes with a female who has blue eyes and answer the following questions. 1. What are the Genotype possibilities? 2. What is the Genotype ratio? 3. What are the Phenotype possibilities? 4. What is the Phenotype ratio? COPYRIGHT CMASSENGALE 60

BELL RINGER # 3 Tall is dominant over short, Brown eyes are dominant over green CROSS A HETEROZYGOUS TALL, HETEROZYGOUS BROWN EYED INDIVIDUAL WITH A HETEROZYGOUS TALL, GREEN EYED PERSON 1. _______ X ____ 2. (FOIL OR 4 SQUARE) 3. Do a 16 Punnett square 4. Offspring’s genotype possibilities 5. Offspring’s genotype ratio 6. Offspring’s phenotype possibilities 7. Offspring’s phenotype ratio 8. *** probability of having a short, green eyed girl 9. *** probability of having a tall, green eyed boy COPYRIGHT CMASSENGALE 61