Punnett Squares

1. Punnett Squares Punnett Squares • Method used to calculate the probable offspring genotypes • Steps to creating Punnett Squares: • Get the parent’s genotypesEx: ZZ, Zz, zz • Draw a Punnett Square • Put the parent’s genotypes on the top and the left side • Drop the alleles down from the top • Slide the alleles over from the left side • Each box is worth 25% zz Z Z Z Z z z Z Z z z

2. Punnett Squares Punnett Squares • Punnett Example: • Father Genotype: Aa • Mother Genotype: AA Possible Genotypes: 50% AA 50% AaPossible Phenotypes: 100% Dominant Trait

3. Punnett Squares Punnett Squares • Punnett Example: Tongue curling is a dominant trait: Dominant allele = C Recessive allele = c Homozygous dominant = ______ Homozygous recessive = ______ Heterozygous = ______ People heterozygous for tongue curlingcan curl their tongue. T / F A homozygousrecessive mom for tongue curling and a heterozygous father want to know if their children will be able to curl their tongues. Calculate the genotype and phenotype percentages for the offspring.

4. Punnett Squares Punnett Square Examples • Punnett Example: Brown hair is dominant over blonde hair: Dominant allele = B Recessive allele = b Homozygous dominant = ______ Homozygous recessive = ______ Heterozygous = ______ Genotypes: Phenotypes:

5. Punnett Squares Punnett Square Examples • Punnett Example: Purple flowers are dominant over white flowers Dominant allele = P Recessive allele = p Homozygous dominant = ______ Homozygous recessive = ______ Heterozygous = ______ Genotypes: Phenotypes:

6. Punnett Square Examples • Punnett Example: Round flowers is dominant over pointed flowers Dominant allele = R Recessive allele = r Homozygous dominant = ______ Homozygous recessive = ______ Heterozygous = ______ Genotypes: Phenotypes:

7. Punnett Square Examples • Punnett Example: Smooth corn kernels are dominant over wrinkled Dominant allele = S Recessive allele = s Homozygous dominant = ______ Homozygous recessive = ______ Heterozygous = ______ Genotypes: Phenotypes: