Can you predict what offspring will look like? PUNNETT SQUARES

PUNNETT SQUARES-WHAT IS THE PURPOSE? ORGANIZE GENETIC INFORMATION ORGANIZE GENETIC INFORMATION PREDICT THE RESULTS OF A GENETIC CROSS PREDICT THE RESULTS OF A GENETIC CROSS SHOWS GENOTYPES AND PHENOTYPES OF THE OFFSPRING SHOWS GENOTYPES AND PHENOTYPES OF THE OFFSPRING It was proposed by the English geneticist, Reginald Punnett It was proposed by the English geneticist, Reginald Punnett

Phenotype the observable physical characteristics of an organism the things you can see The expressions of genotypes

GENOTYPE LETTER COMBINATION FOR TRAITS LETTER COMBINATION FOR TRAITS LETTERS ARE IN PAIRS LETTERS ARE IN PAIRS EX. TT, T t, t t EX. TT, T t, t t

Dominant & recessive alleles (Fig. 10.7):

1. Write down the genotypes of both parents 1. Write down the genotypes of both parents Male parent = Tt Male parent = Tt Female parent = Tt Female parent = Tt 2. Write down the possible gametes each parent can make. 2. Write down the possible gametes each parent can make. Male gametes: T or t Male gametes: T or t Female gametes: T or t Female gametes: T or t Punnett Squares

3. Create an empty Punnett square 3. Create an empty Punnett square 4. Fill in the Punnett square with the possible genotypes of the offspring 4. Fill in the Punnett square with the possible genotypes of the offspring

Understanding Physical Anthropology and Archaeology, 8th ed., p. 55 Punnett square with genotypes and phenotypes

1.Purebred Dominant x Purebred Recessive (PP x pp) Genotype Ratio: All Pp Phenotype Ratio: All Dominant

2. Purebred Dominant x Hybrid (BB X Bb) Genotype Ratio: ½ BB: ½ Bb 1BB:1Bb 50%BB:50%Bb Phenotype Ratio: All Dominant

3. Hybrid x Hybrid (Bb x Bb) Genotype Ratio: ¼ BB: ½ Bb: ¼ bb 1BB:2Bb:1bb 25%BB:50%Bb:25%bb Phenotype Ratio: 3Dominant: 1Recessive

4.) Hybrid x Purebred recessive Bb x bb Genotype Ratio 2Bb:2bb Phenotype Ratio ½ Dominant: 1/2 Recessive

Summary of the 4 crosses Cross Genotype Ratio Phenotype Ratio BB x bb All Bb All Dominant BB x Bb 2BB:2Bb All Dominant Bb x Bb 1BB:2Bb:1bb 3 Dominant: 1 Recessive Bb x bb 2Bb:2bb 2 Dominant: 2 Recessive

Dihybrid Cross A dihybrid cross examines 2 different genes. A dihybrid cross examines 2 different genes. RULES: RULES: 1. Do not cross traits 2. Capital letters must go first for each trait 3. Each organism is going to have two genotypes and phenotypes

Dihybrid Cross: F1 cross

Sections of DNA are now called ________. Sections of DNA are now called ________. _______ are different forms of the same gene. _______ are different forms of the same gene. An individual with two identical alleles is termed An individual with two identical alleles is termed ____________. ____________. An individual with two different alleles, is termed An individual with two different alleles, is termed ____________. ____________. ____________ refers to the letter combination for traits. ____________ refers to the letter combination for traits. ____________ refers to the physical appearance of an organism. ____________ refers to the physical appearance of an organism. Vocab Review

Sections of DNA are now called genes. Sections of DNA are now called genes. Alleles are different forms of the same gene Alleles are different forms of the same gene An individual with two identical alleles is termed homozygous An individual with two identical alleles is termed homozygous An individual with two different alleles, is termed heterozygous An individual with two different alleles, is termed heterozygous Genotype refers to the letter combination for traits. Genotype refers to the letter combination for traits. Phenotype refers to the physical appearance of an organism. Phenotype refers to the physical appearance of an organism.