Heredity and Punnett Squares

The passing of traits from parents to offspring through genes.

A diagram used to predict the outcome of a genetic cross by showing the possible allele combinations from the parents.

Having two identical alleles for a particular gene (e.g., AA or aa).

Having two different alleles for a particular gene (e.g., Aa).

An allele that expresses its trait even when only one copy is present (e.g., T in Tt).

An allele that only expresses its trait when two copies are present (e.g., aa).

The visible or physical trait resulting from the allele pair (e.g., brown hair).

The genetic combination of alleles in the allele pair (e.g., AA, Aa, or aa).

Count the number of times the desired trait appears in the offspring combinations and divide by the total number of combinations.

There is a 25% chance that any given offspring will express that trait.