Punnett Squares Punnett Squares Z Z Z Z Z z z z z z z Method used to calculate the probable offspring genotypes Steps to creating Punnett Squares: Get the parent’s genotypes Ex: 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% z z Z Z Z z z Z Z z z

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

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 curling can curl their tongue. T / F A homozygous recessive 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.

Punnett Square Examples 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:

Punnett Square Examples 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:

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:

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: