Punnett Squares

Probability Probability is the likelihood that a particular event will occur. Punnett Squares: Show all possible combinations of a genetic cross. Determine the genes for a particular set of offspring.

Example Punnett Square Pure Bred Cross Key: H= Dominant (tall plant) h= Recessive (short plant)

Phenotype & Genotype A phenotype describes what an organism looks like. A genotype describes the allele combination of an organism.

Example Phenotype & Genotype Phenotype: (tall or short) Tall: 100% Short: 0% Genotype: (allele combinations) Hybrid: 100% Pure Dominant: 0% Pure Recessive: 0%

Another Example Cross a hybrid (Hh) with another hybrid (Hh) Draw a punnett square showing this cross (TRY THIS ONE BY YOURSELF BEFORE CHECKING YOUR WORK!)

Hybrid Cross Example Phenotype: Genotype: Tall: 75% Short: 25% Pure Dominant: 25% Pure Recessive: 25%